diff --git a/docs/en/changes/changes.md b/docs/en/changes/changes.md
index 4e9032902dd8..9340d9ef4217 100644
--- a/docs/en/changes/changes.md
+++ b/docs/en/changes/changes.md
@@ -2,6 +2,7 @@
 
 #### Project
 
+* Move the DSL class-loading machinery under `core/dsl`. `core/classloader` held only DSL types — `RuleClassLoader`, `DSLClassLoaderManager`, `ClassLoaderGc`, `UnloadProbePayload` and `BytecodeClassDefiner` — so it is now `core/dsl/classloader`, and `Catalog` moves to `core/dsl` because a rule-file taxonomy is not a class-loading concern. Three copies of the "define a generated class into the right loader" dispatch (MAL, LAL, `MeterSystem`) collapse into a static `BytecodeClassDefiner.define`, which also gives the JDK 17 `--add-opens` rationale one home instead of four. Three of the four copies of the generated-class dump-directory lookup become `DslGeneratedFileWriter.resolveClassDumpDir`; OAL keeps its own, because its debug flag is settable independently of the environment variable and two tests rely on that. No behaviour change.
 * Extend the `GET /inspect/entities` admin API to inspect a metric persisted by **any** OAP, even one this node does not define locally. When the metric is unknown to the local registry, the caller supplies `valueColumn` + `valueType` and the storage backend resolves the physical index/table/group from its own running config (no DB schema/table-metadata read): ES uses the merged `metrics-all` index + `metric_table` discriminator, JDBC probes the node's function tables by the `table_name` discriminator, and BanyanDB synthesizes a read-only measure schema. Scope is no longer required — the `entity_id` is decoded structurally (service / 2nd-level / relations) with a generic `name` leaf. Locally-defined metrics keep the exact field names, scope, and `mqeEntity` as before.
 * Add the `POST /inspect/values` admin API — read the value series of a metric persisted by **another** OAP (one this node does not define locally) by supplying its `{valueColumn, valueType}`. The real MQE engine runs over a request-scoped `InspectQueryContext` overlay (provide-if-absent — the local catalog always wins) that makes the foreign metric look registered to every read path: `ValueColumnMetadata` resolves its value column / type / scope, and the storage location registries resolve where it lives (`MetadataRegistry` synthesizes a BanyanDB measure schema, `IndexController` resolves the ES `metrics-all` index, `TableHelper` probes the JDBC function tables), so the read returns the native MQE `ExpressionResult` with no per-DAO special-casing. Admin-only (a forced read this OAP cannot validate); not mirrored onto the public REST / GraphQL surface. See the [Inspect API](../setup/backend/admin-api/inspect.md).
 * Remove the always-on alarm-to-event conversion (`EventHookCallback`). A triggered alarm is no longer synthesized into the events pipeline as an `Alarm`/`AlarmRecovery` event; events now originate only from real event sources (agents, SkyWalking CLI, Kubernetes Event Exporter). Alarms remain available through the alarm store (`getAlarm`/`queryAlarms`) and the configured alarm hooks. This drops a documented "Known Event" and removes 1-2 synthetic event records per alarm fire.
@@ -256,7 +257,7 @@
 
 #### OAP Server
 * Fix LAL's `segmentId` and `spanId` extractor statements, which the grammar accepted and the parser never implemented. `LALParser.g4` declares `traceIdStatement`, `segmentIdStatement` and `spanIdStatement`, and the codegen already carried `setSegmentId`/`setSpanId` in its setter table, but `LALScriptParser.visitExtractorStatement` had a branch for only the first of the three. The remaining alternatives fell through to a line that assumed whatever was left had to be an `ifStatement`, so a rule writing `segmentId ...` failed at boot with a `NullPointerException` naming `IfStatementContext` — for a rule line containing no `if`. Both statements now work, and an unhandled extractor statement reports its own rule line instead of throwing. Existing log records are unaffected: `LogBuilder` copies trace id, segment id and span id straight from the log's metadata, and only skips that copy when a rule has set them — which no shipped rule did, which is why the gap went unnoticed. Dedicated execution tests now cover reading all three fields from `log.traceContext.*` and writing all three from an extractor.
-* Remove dead code from the DSL subsystem and correct the shared kernel's own documentation. Deleted `DslContentHash` (a byte-identical, zero-caller twin of the live `ContentHash`), the unused `oal-rt` metrics-function registry, `LogAnalyzerFactory`, `LALCodegenHelper.METADATA_GETTER_ALIASES` (a permanently empty map whose reader branch could never execute — the DSL-name-to-getter mismatch it existed for no longer exists, since `LogMetadata.TraceContext` names the field `traceSegmentId` directly), and three unreferenced members. Three kernel classes carried javadoc asserting consumers that do not exist — `DSLClassLoaderManager` claimed the MAL and LAL compile paths reach for its singleton, `LogDataDebugDump` claimed core renders through it, and `DslContentHash` instructed the reader to consolidate toward the dead copy; a false rationale in a shared kernel is an instruction to the next contributor, so those are now what the call sites actually support. `OALDebug`, `OALDebugRecorder` and `DebugHolderProvider` now record why they sit in core while MAL's and LAL's equivalents do not: `dsl-debugging` declares no `oal-rt` dependency, so they cannot move. `dsl-debugging` also now declares its `server-core` dependency directly instead of inheriting it transitively.
+* Remove dead code from the DSL subsystem and correct the shared kernel's own documentation. Deleted `DslContentHash` (a byte-identical, zero-caller twin of the live `ContentHash`), the unused `oal-rt` metrics-function registry, `LogAnalyzerFactory`, `LALCodegenHelper.METADATA_GETTER_ALIASES` (a permanently empty map whose reader branch could never execute — the DSL-name-to-getter mismatch it existed for no longer exists, since `LogMetadata.TraceContext` names the field `traceSegmentId` directly), and three unreferenced members. Three kernel classes carried javadoc asserting consumers that do not exist — `DSLClassLoaderManager` claimed the MAL and LAL compile paths reach for its singleton, `LogDataDebugDump` claimed core renders through it, and `DslContentHash` instructed the reader to consolidate toward the dead copy; a false rationale in a shared kernel is an instruction to the next contributor, so those are now what the call sites actually support. `OALDebug`, `OALDebugRecorder` and `DebugHolderProvider` now record why they sit in core while MAL's and LAL's equivalents do not: `dsl-debugging` declares no `oal-rt` dependency, so they cannot move.
 * Unify source attribution for every generated DSL class, so a stack frame from OAL, MAL, LAL or Hierarchy code leads back to the rule that produced it.
   - `SourceFile` now names the RULE and its line, then the generated class file: `(otel-rules/activemq/activemq-broker.yaml:32)otel_rules_activemq_activemq_broker_L32_service_meter.java`. The `.java` generated source file is written only under `SW_DYNAMIC_CLASS_ENGINE_DEBUG`, so in a default deployment naming it named nothing; the class name cannot substitute because sanitising maps `/`, `-` and `.` all to `_` and drops the extension.
   - The `_L<n>_` segment was the rules-list index rather than a line, so every file's first rule reported as `L0`. It now carries the rule's real line, resolved by the loaders themselves — including Zabbix and Hierarchy, which supplied no coordinate at all, and the runtime-rule hot-update paths for MAL and LAL, which disagreed with their own boot loaders.
diff --git a/oap-server/analyzer/hierarchy/src/main/java/org/apache/skywalking/oap/server/core/config/v2/compiler/HierarchyRuleClassGenerator.java b/oap-server/analyzer/hierarchy/src/main/java/org/apache/skywalking/oap/server/core/config/v2/compiler/HierarchyRuleClassGenerator.java
index af8b16f94cd6..71d054887d75 100644
--- a/oap-server/analyzer/hierarchy/src/main/java/org/apache/skywalking/oap/server/core/config/v2/compiler/HierarchyRuleClassGenerator.java
+++ b/oap-server/analyzer/hierarchy/src/main/java/org/apache/skywalking/oap/server/core/config/v2/compiler/HierarchyRuleClassGenerator.java
@@ -30,9 +30,7 @@
 import javassist.CtNewConstructor;
 import javassist.CtNewMethod;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.skywalking.oap.server.core.WorkPath;
 import org.apache.skywalking.oap.server.core.config.v2.compiler.hierarchy.rule.rt.HierarchyRulePackageHolder;
-import org.apache.skywalking.oap.server.library.util.StringUtil;
 import org.apache.skywalking.oap.server.core.query.type.Service;
 import org.apache.skywalking.oap.server.core.dsl.DslJavaSourceText;
 
@@ -79,9 +77,7 @@ public final class HierarchyRuleClassGenerator {
 
     public HierarchyRuleClassGenerator() {
         this(ClassPool.getDefault());
-        if (StringUtil.isNotEmpty(System.getenv("SW_DYNAMIC_CLASS_ENGINE_DEBUG"))) {
-            classOutputDir = new File(WorkPath.getPath().getParentFile(), "hierarchy-rt");
-        }
+        classOutputDir = DslGeneratedFileWriter.resolveClassDumpDir("hierarchy");
     }
 
     public HierarchyRuleClassGenerator(final ClassPool classPool) {
diff --git a/oap-server/analyzer/log-analyzer/src/main/java/org/apache/skywalking/oap/log/analyzer/v2/compiler/LALClassGenerator.java b/oap-server/analyzer/log-analyzer/src/main/java/org/apache/skywalking/oap/log/analyzer/v2/compiler/LALClassGenerator.java
index b004cd6bc8a0..9c50bbea9371 100644
--- a/oap-server/analyzer/log-analyzer/src/main/java/org/apache/skywalking/oap/log/analyzer/v2/compiler/LALClassGenerator.java
+++ b/oap-server/analyzer/log-analyzer/src/main/java/org/apache/skywalking/oap/log/analyzer/v2/compiler/LALClassGenerator.java
@@ -19,12 +19,12 @@
 
 import org.apache.skywalking.oap.server.core.dsl.DslGeneratedFileWriter;
 import java.io.File;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
+import javassist.CannotCompileException;
 import javassist.ClassPool;
 import javassist.CtClass;
 import javassist.CtNewConstructor;
@@ -35,12 +35,10 @@
 import org.apache.skywalking.oap.log.analyzer.v2.provider.LALConfigs;
 import org.apache.skywalking.oap.server.core.dsl.DslClassNaming;
 import org.apache.skywalking.oap.server.core.dsl.DslSourceRef;
-import org.apache.skywalking.oap.server.core.classloader.BytecodeClassDefiner;
+import org.apache.skywalking.oap.server.core.dsl.classloader.BytecodeClassDefiner;
 import org.apache.skywalking.oap.server.core.dsl.debug.DSLDebugCodegenSwitch;
 import org.apache.skywalking.oap.server.core.source.LogBuilder;
 import org.apache.skywalking.oap.log.analyzer.v2.dsl.LalExpression;
-import org.apache.skywalking.oap.server.core.WorkPath;
-import org.apache.skywalking.oap.server.library.util.StringUtil;
 import org.apache.skywalking.oap.server.core.dsl.DslJavaSourceText;
 
 /**
@@ -219,9 +217,7 @@ void restoreProtoVarState(final Object[] state) {
 
     public LALClassGenerator() {
         this(ClassPool.getDefault(), null);
-        if (StringUtil.isNotEmpty(System.getenv("SW_DYNAMIC_CLASS_ENGINE_DEBUG"))) {
-            classOutputDir = new File(WorkPath.getPath().getParentFile(), "lal-rt");
-        }
+        classOutputDir = DslGeneratedFileWriter.resolveClassDumpDir("lal");
     }
 
     public LALClassGenerator(final ClassPool classPool) {
@@ -508,26 +504,12 @@ private String buildSourceText(final CtClass ctClass,
      * (startup path: class lands in the OAP app loader alongside
      * {@link LalExpressionPackageHolder}).
      *
-     * <p>{@link BytecodeClassDefiner} loaders (the runtime-rule {@code RuleClassLoader})
-     * receive the {@code CtClass.toBytecode()} bytes via their public {@code defineClass}
-     * — bypasses Javassist's deprecated {@code toClass(loader, ProtectionDomain)} reflection
-     * path so we don't need {@code --add-opens java.base/java.lang} on the OAP container.
-     * Same shape as {@code MALClassGenerator}; both DSLs share the contract.
+     * <p>Which of the two definition paths applies, and why the
+     * {@link BytecodeClassDefiner} one exists at all, is documented on
+     * {@link BytecodeClassDefiner#define}.
      */
-    private Class<?> defineClass(final CtClass ctClass) throws javassist.CannotCompileException {
-        if (targetClassLoader != null) {
-            if (targetClassLoader instanceof BytecodeClassDefiner) {
-                try {
-                    return ((BytecodeClassDefiner) targetClassLoader)
-                        .defineClass(ctClass.getName(), ctClass.toBytecode());
-                } catch (final IOException e) {
-                    throw new javassist.CannotCompileException(
-                        "failed to serialise " + ctClass.getName() + " bytes", e);
-                }
-            }
-            return ctClass.toClass(targetClassLoader, null);
-        }
-        return ctClass.toClass(LalExpressionPackageHolder.class);
+    private Class<?> defineClass(final CtClass ctClass) throws CannotCompileException {
+        return BytecodeClassDefiner.define(ctClass, targetClassLoader, LalExpressionPackageHolder.class);
     }
 
     private static boolean hasParsedAccess(
diff --git a/oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/v2/compiler/MALClassGenerator.java b/oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/v2/compiler/MALClassGenerator.java
index abbee709e216..5d4e98c63677 100644
--- a/oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/v2/compiler/MALClassGenerator.java
+++ b/oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/v2/compiler/MALClassGenerator.java
@@ -20,23 +20,21 @@
 import org.apache.skywalking.oap.server.core.dsl.DslGeneratedFileWriter;
 import org.apache.skywalking.oap.server.core.dsl.DslSourceRef;
 import java.io.File;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javassist.CannotCompileException;
 import javassist.ClassPool;
 import javassist.CtClass;
 import javassist.CtNewConstructor;
 import javassist.CtNewMethod;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.skywalking.oap.meter.analyzer.v2.compiler.rt.MalExpressionPackageHolder;
-import org.apache.skywalking.oap.server.core.classloader.BytecodeClassDefiner;
+import org.apache.skywalking.oap.server.core.dsl.classloader.BytecodeClassDefiner;
 import org.apache.skywalking.oap.meter.analyzer.v2.dsl.ExpressionMetadata;
 import org.apache.skywalking.oap.meter.analyzer.v2.dsl.MalExpression;
 import org.apache.skywalking.oap.meter.analyzer.v2.dsl.MalFilter;
-import org.apache.skywalking.oap.server.core.WorkPath;
-import org.apache.skywalking.oap.server.library.util.StringUtil;
 import org.apache.skywalking.oap.server.core.dsl.DslJavaSourceText;
 
 /**
@@ -76,10 +74,7 @@ public final class MALClassGenerator {
 
     public MALClassGenerator() {
         this(createClassPool(), null);
-        if (StringUtil.isNotEmpty(System.getenv("SW_DYNAMIC_CLASS_ENGINE_DEBUG"))) {
-            bytecodeHelper.setClassOutputDir(
-                new File(WorkPath.getPath().getParentFile(), "mal-rt"));
-        }
+        bytecodeHelper.setClassOutputDir(DslGeneratedFileWriter.resolveClassDumpDir("mal"));
     }
 
     private static ClassPool createClassPool() {
@@ -251,29 +246,12 @@ private static String wrapMalFilterSource(final CtClass ctClass, final String fi
      * (startup path: class lands in the OAP app loader alongside
      * {@link MalExpressionPackageHolder}).
      *
-     * <p>When {@code targetClassLoader} implements
-     * {@link org.apache.skywalking.oap.server.core.classloader.BytecodeClassDefiner
-     * BytecodeClassDefiner} (the runtime-rule {@code RuleClassLoader} does), we hand
-     * the loader the {@code CtClass.toBytecode()} bytes and let it invoke its public
-     * {@code defineClass} directly — no Javassist {@code toClass(loader,
-     * ProtectionDomain)} reflection, no {@code --add-opens java.base/java.lang}
-     * requirement on JDK 17+. Otherwise we fall back to the legacy 2-arg toClass for
-     * back-compat, but no shipped loader uses that path today.
+     * <p>Which of the two definition paths applies, and why the
+     * {@link BytecodeClassDefiner} one exists at all, is documented on
+     * {@link BytecodeClassDefiner#define}.
      */
-    private Class<?> defineClass(final CtClass ctClass) throws javassist.CannotCompileException {
-        if (targetClassLoader != null) {
-            if (targetClassLoader instanceof BytecodeClassDefiner) {
-                try {
-                    return ((BytecodeClassDefiner) targetClassLoader)
-                        .defineClass(ctClass.getName(), ctClass.toBytecode());
-                } catch (final IOException e) {
-                    throw new javassist.CannotCompileException(
-                        "failed to serialise " + ctClass.getName() + " bytes", e);
-                }
-            }
-            return ctClass.toClass(targetClassLoader, null);
-        }
-        return ctClass.toClass(MalExpressionPackageHolder.class);
+    private Class<?> defineClass(final CtClass ctClass) throws CannotCompileException {
+        return BytecodeClassDefiner.define(ctClass, targetClassLoader, MalExpressionPackageHolder.class);
     }
 
     /**
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImpl.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImpl.java
index 5a6872d4ad1f..0c195f8c7bc2 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImpl.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImpl.java
@@ -42,7 +42,7 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.InstallOutcome;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.Sample;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.SessionLimits;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 
 /**
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALDebugRecorderFactory.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALDebugRecorderFactory.java
index 7e418ff8bd25..8c7b4448087e 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALDebugRecorderFactory.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALDebugRecorderFactory.java
@@ -22,7 +22,7 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugRecorderFactory;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.Granularity;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.SessionLimits;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALHolderRegistry.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALHolderRegistry.java
index caa022833501..1523e76e8cc2 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALHolderRegistry.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/lal/LALHolderRegistry.java
@@ -21,7 +21,7 @@
 import java.util.concurrent.ConcurrentHashMap;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugHolderLookup;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 import org.apache.skywalking.oap.server.library.module.Service;
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALDebugRecorderFactory.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALDebugRecorderFactory.java
index ef26df26ff74..0036ccdc1121 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALDebugRecorderFactory.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALDebugRecorderFactory.java
@@ -21,7 +21,7 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.AbstractDebugRecorder;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugRecorderFactory;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.SessionLimits;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALHolderRegistry.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALHolderRegistry.java
index 5f3cfea27442..627a21baa9ec 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALHolderRegistry.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/mal/MALHolderRegistry.java
@@ -21,7 +21,7 @@
 import java.util.concurrent.ConcurrentHashMap;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugHolderLookup;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 import org.apache.skywalking.oap.server.library.module.Service;
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/module/DSLDebuggingModuleProvider.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/module/DSLDebuggingModuleProvider.java
index 12477d4a0ed8..fb57c2e84023 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/module/DSLDebuggingModuleProvider.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/module/DSLDebuggingModuleProvider.java
@@ -40,7 +40,7 @@
 import org.apache.skywalking.oap.server.admin.server.cluster.AdminClusterChannelManager;
 import org.apache.skywalking.oap.server.admin.server.module.AdminServerModule;
 import org.apache.skywalking.oap.server.core.analysis.DispatcherManager;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.server.GRPCHandlerRegister;
 import org.apache.skywalking.oap.server.core.source.SourceReceiver;
 import org.apache.skywalking.oap.server.core.source.SourceReceiverImpl;
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALDebugRecorderFactory.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALDebugRecorderFactory.java
index 152429e9ce0e..0fbcbf59ce68 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALDebugRecorderFactory.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALDebugRecorderFactory.java
@@ -21,7 +21,7 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.AbstractDebugRecorder;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugRecorderFactory;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.SessionLimits;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALHolderLookup.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALHolderLookup.java
index 12329521517c..70a8f9a1f88c 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALHolderLookup.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/oal/OALHolderLookup.java
@@ -21,7 +21,7 @@
 import lombok.RequiredArgsConstructor;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugHolderLookup;
 import org.apache.skywalking.oap.server.core.analysis.DispatcherManager;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.DebugHolderProvider;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
diff --git a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/rest/DSLDebuggingRestHandler.java b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/rest/DSLDebuggingRestHandler.java
index 655c2833e32d..65e1805ceab9 100644
--- a/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/rest/DSLDebuggingRestHandler.java
+++ b/oap-server/server-admin/dsl-debugging/src/main/java/org/apache/skywalking/oap/server/admin/dsl/debugging/rest/DSLDebuggingRestHandler.java
@@ -52,7 +52,7 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.Granularity;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.Sample;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.SessionLimits;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 
 /**
diff --git a/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImplTest.java b/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImplTest.java
index 907fdc99046c..6ca14b3bdce4 100644
--- a/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImplTest.java
+++ b/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/cluster/DSLDebuggingClusterServiceImplTest.java
@@ -39,7 +39,7 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugRecorderFactory;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.DebugSessionRegistry;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.session.SessionLimits;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 import org.junit.jupiter.api.AfterEach;
diff --git a/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/DebugSessionRegistryTest.java b/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/DebugSessionRegistryTest.java
index dc9b3c6d655c..058efa0beda3 100644
--- a/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/DebugSessionRegistryTest.java
+++ b/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/DebugSessionRegistryTest.java
@@ -24,7 +24,7 @@
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 import org.junit.jupiter.api.Test;
diff --git a/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/RecorderCapTest.java b/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/RecorderCapTest.java
index 784a9c9cfce7..7c2605c6e13e 100644
--- a/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/RecorderCapTest.java
+++ b/oap-server/server-admin/dsl-debugging/src/test/java/org/apache/skywalking/oap/server/admin/dsl/debugging/session/RecorderCapTest.java
@@ -18,7 +18,7 @@
 
 package org.apache.skywalking.oap.server.admin.dsl.debugging.session;
 
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.core.dsl.debug.GateHolder;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 import org.junit.jupiter.api.Test;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplier.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplier.java
index b3b32544ee43..ab7d68cf9e3a 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplier.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplier.java
@@ -35,9 +35,9 @@
 import org.apache.skywalking.oap.log.analyzer.v2.provider.LALConfigs;
 import org.apache.skywalking.oap.server.core.dsl.DslYamlLineIndex;
 import org.apache.skywalking.oap.log.analyzer.v2.provider.log.listener.LogFilterListener;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
-import org.apache.skywalking.oap.server.core.classloader.RuleClassLoader;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.classloader.RuleClassLoader;
 import org.apache.skywalking.oap.server.library.module.ModuleManager;
 import org.apache.skywalking.oap.server.receiver.runtimerule.layer.AppliedClaims;
 import org.apache.skywalking.oap.server.receiver.runtimerule.layer.LayerClaim;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplier.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplier.java
index e0b969b3fa29..15335c3d1f35 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplier.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplier.java
@@ -37,9 +37,9 @@
 import org.apache.skywalking.oap.server.core.CoreModule;
 import org.apache.skywalking.oap.server.core.analysis.LayerDefinition;
 import org.apache.skywalking.oap.server.core.analysis.meter.MeterSystem;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
-import org.apache.skywalking.oap.server.core.classloader.RuleClassLoader;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.classloader.RuleClassLoader;
 import org.apache.skywalking.oap.server.core.storage.StorageException;
 import org.apache.skywalking.oap.server.core.storage.model.StorageManipulationOpt;
 import org.apache.skywalking.oap.server.library.module.ModuleManager;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/ApplyContext.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/ApplyContext.java
index 2f9b49575008..10d83787206e 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/ApplyContext.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/ApplyContext.java
@@ -40,7 +40,7 @@
  * method takes one as a parameter and uses it transactionally.
  *
  * <p>Classloader retire / install is NOT exposed on the context. Engines reach the
- * {@link org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager#INSTANCE}
+ * {@link org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager#INSTANCE}
  * singleton directly when they need to mint or drop a per-file loader; threading the manager
  * through every context would add coupling without value (lifetime is process-wide, not
  * per-call).
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/RuleEngine.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/RuleEngine.java
index b6000636c2ec..15b5d6f309f0 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/RuleEngine.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/RuleEngine.java
@@ -21,7 +21,7 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Consumer;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.core.storage.management.RuntimeRuleManagementDAO;
 import org.apache.skywalking.oap.server.core.storage.model.StorageManipulationOpt;
 import org.apache.skywalking.oap.server.library.module.ModuleManager;
@@ -265,7 +265,7 @@ public interface RuleEngine<C extends ApplyContext> {
      * scheduler stamps {@code applyError} on the snapshot and surfaces to the caller.
      *
      * <p>{@code kind} controls how the per-file classloader is tagged in {@link
-     * org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager}:
+     * org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager}:
      * {@link DSLClassLoaderManager.Kind#RUNTIME} for {@code /addOrUpdate} and tick paths,
      * {@link DSLClassLoaderManager.Kind#BUNDLED} for the {@code /delete?mode=revertToBundled}
      * path that re-installs the bundled YAML through the standard apply pipeline. The kind
@@ -296,7 +296,7 @@ CompiledDSL compile(RuntimeRuleManagementDAO.RuntimeRuleFile file,
     /**
      * Phase: commit. Swap the in-memory cache (engine-owned applied state + appliedContent
      * for this key), promote the freshly-built classloader via {@link
-     * org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager#commit} and
+     * org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager#commit} and
      * retire any displaced prior loader through the manager, fire alarm-reset for the
      * affected metric name set via the context's alarmResetter callback. From this call
      * onward the bundle is live; up to this call all phases can be rolled back cleanly.
@@ -345,7 +345,7 @@ CompiledDSL compile(RuntimeRuleManagementDAO.RuntimeRuleFile file,
      * bundled rule from {@link
      * org.apache.skywalking.oap.server.core.rule.ext.StaticRuleRegistry} (if any) and bring
      * it back into service via a fresh {@code bundled:} loader from
-     * {@link org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager}.
+     * {@link org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager}.
      *
      * <p>Returns {@code true} when a bundled rule was found and reinstalled; {@code false}
      * when no bundled rule exists for this key (the rule is genuinely gone) or the engine
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/lal/LalRuleEngine.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/lal/LalRuleEngine.java
index 408c54c1cfd9..e7c071db6441 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/lal/LalRuleEngine.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/lal/LalRuleEngine.java
@@ -33,8 +33,8 @@
 import org.apache.skywalking.oap.log.analyzer.v2.provider.log.listener.LogFilterListener;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.lal.LALHolderRegistry;
 import org.apache.skywalking.oap.server.admin.dsl.debugging.module.DSLDebuggingModule;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
 import org.apache.skywalking.oap.server.core.rule.ext.StaticRuleRegistry;
 import org.apache.skywalking.oap.server.core.storage.management.RuntimeRuleManagementDAO;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/mal/MalRuleEngine.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/mal/MalRuleEngine.java
index b9a5de00b476..aeac8c660b0b 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/mal/MalRuleEngine.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/engine/mal/MalRuleEngine.java
@@ -37,10 +37,10 @@
 import org.apache.skywalking.oap.server.admin.dsl.debugging.module.DSLDebuggingModule;
 import org.apache.skywalking.oap.server.core.CoreModule;
 import org.apache.skywalking.oap.server.core.analysis.meter.MeterSystem;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.core.dsl.debug.RuleKey;
-import org.apache.skywalking.oap.server.core.classloader.RuleClassLoader;
+import org.apache.skywalking.oap.server.core.dsl.classloader.RuleClassLoader;
 import org.apache.skywalking.oap.server.core.rule.ext.StaticRuleRegistry;
 import org.apache.skywalking.oap.server.core.storage.StorageModule;
 import org.apache.skywalking.oap.server.core.storage.management.RuntimeRuleManagementDAO;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLManager.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLManager.java
index c9d2ece6fb6f..12bd0837a40e 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLManager.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLManager.java
@@ -32,7 +32,7 @@
 import org.apache.skywalking.oap.server.receiver.runtimerule.metrics.LockMetrics;
 import org.apache.skywalking.oap.server.core.alarm.AlarmKernelService;
 import org.apache.skywalking.oap.server.core.alarm.AlarmModule;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.core.storage.StorageModule;
 import org.apache.skywalking.oap.server.core.management.runtimerule.RuntimeRule;
 import org.apache.skywalking.oap.server.core.storage.management.RuntimeRuleManagementDAO;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeApply.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeApply.java
index 3d924d37f6c1..280cf1be2a4e 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeApply.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeApply.java
@@ -19,7 +19,7 @@
 package org.apache.skywalking.oap.server.receiver.runtimerule.reconcile;
 
 import lombok.extern.slf4j.Slf4j;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.core.storage.management.RuntimeRuleManagementDAO;
 import org.apache.skywalking.oap.server.receiver.runtimerule.engine.ApplyContext;
 import org.apache.skywalking.oap.server.receiver.runtimerule.engine.ApplyInputs;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeDelete.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeDelete.java
index 0579e9771576..c9798ac771e4 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeDelete.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeDelete.java
@@ -26,7 +26,7 @@
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Consumer;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.core.rule.ext.StaticRuleRegistry;
 import org.apache.skywalking.oap.server.core.storage.management.RuntimeRuleManagementDAO;
 import org.apache.skywalking.oap.server.core.storage.model.StorageManipulationOpt;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeUnregister.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeUnregister.java
index 89de25653449..239af4517e43 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeUnregister.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLRuntimeUnregister.java
@@ -46,7 +46,7 @@
  * <p>After a successful teardown, the engine's {@code installBundled} hook is invoked so any
  * bundled rule that the now-removed runtime override was masking gets brought back into
  * service via a fresh {@code bundled:} loader from
- * {@link org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager}.
+ * {@link org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager}.
  *
  * <p><b>{@code invokeAlarmOnRemove}.</b> Two legitimate call modes:
  * <ul>
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLScriptKey.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLScriptKey.java
index 1f8c59084d33..f0b038af7d5a 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLScriptKey.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/reconcile/DSLScriptKey.java
@@ -19,10 +19,6 @@
 package org.apache.skywalking.oap.server.receiver.runtimerule.reconcile;
 
 import org.apache.skywalking.oap.server.receiver.runtimerule.apply.LalFileApplier;
-import org.apache.skywalking.oap.server.receiver.runtimerule.engine.RuleEngine;
-import org.apache.skywalking.oap.server.receiver.runtimerule.engine.RuleEngineRegistry;
-import org.apache.skywalking.oap.server.receiver.runtimerule.engine.lal.LalRuleEngine;
-import org.apache.skywalking.oap.server.receiver.runtimerule.engine.mal.MalRuleEngine;
 
 /**
  * Pure key-format helpers shared across the runtime-rule dslManager, REST handler, and
@@ -68,21 +64,4 @@ public static String shortHash(final String hash) {
         return hash.substring(0, 8);
     }
 
-    /**
-     * True for catalogs whose rule files parse as MAL. Routes through the engine registry
-     * rather than a hardcoded string set so a catalog added to {@link MalRuleEngine#supportedCatalogs}
-     * (e.g. {@code telegraf-rules}) is automatically recognised by every {@code isMalCatalog}
-     * caller — no parallel string list to keep in sync.
-     */
-    public static boolean isMalCatalog(final RuleEngineRegistry registry, final String catalog) {
-        final RuleEngine<?> engine = registry.forCatalog(catalog);
-        return engine instanceof MalRuleEngine;
-    }
-
-    /** True for catalogs whose rule files parse as LAL. Same registry-driven routing as
-     *  {@link #isMalCatalog}. */
-    public static boolean isLalCatalog(final RuleEngineRegistry registry, final String catalog) {
-        final RuleEngine<?> engine = registry.forCatalog(catalog);
-        return engine instanceof LalRuleEngine;
-    }
 }
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleRestHandler.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleRestHandler.java
index bdb4dd0c5b74..7b60a4fe311a 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleRestHandler.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleRestHandler.java
@@ -27,7 +27,7 @@
 import com.linecorp.armeria.server.annotation.Param;
 import com.linecorp.armeria.server.annotation.Post;
 import lombok.Getter;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.apache.skywalking.oap.server.library.module.ModuleManager;
 import org.apache.skywalking.oap.server.receiver.runtimerule.cluster.RuntimeRuleClusterClient;
 import org.apache.skywalking.oap.server.receiver.runtimerule.reconcile.DSLManager;
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleService.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleService.java
index 33e8962037ce..ce2e9367a9c3 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleService.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleService.java
@@ -52,11 +52,11 @@
 import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
 import lombok.extern.slf4j.Slf4j;
 import java.nio.charset.StandardCharsets;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
-import org.apache.skywalking.oap.server.core.classloader.DSLClassLoaderManager;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 import org.apache.skywalking.oap.server.admin.server.cluster.AdminClusterChannelManager;
 import org.apache.skywalking.oap.server.admin.server.module.AdminServerModule;
-import org.apache.skywalking.oap.server.core.classloader.RuleClassLoader;
+import org.apache.skywalking.oap.server.core.dsl.classloader.RuleClassLoader;
 import org.apache.skywalking.oap.server.telemetry.api.HistogramMetrics;
 import org.apache.skywalking.oap.server.core.management.runtimerule.RuntimeRule;
 import org.apache.skywalking.oap.server.core.storage.model.StorageManipulationOpt;
@@ -68,6 +68,9 @@
 import org.apache.skywalking.oap.server.receiver.runtimerule.apply.DeltaClassifier;
 import org.apache.skywalking.oap.server.receiver.runtimerule.engine.Classification;
 import org.apache.skywalking.oap.server.receiver.runtimerule.engine.RuleEngine;
+import org.apache.skywalking.oap.server.receiver.runtimerule.engine.RuleEngineRegistry;
+import org.apache.skywalking.oap.server.receiver.runtimerule.engine.lal.LalRuleEngine;
+import org.apache.skywalking.oap.server.receiver.runtimerule.engine.mal.MalRuleEngine;
 import org.apache.skywalking.oap.server.receiver.runtimerule.extension.DbOverrideRuntimeRuleResolver;
 import org.apache.skywalking.oap.server.receiver.runtimerule.layer.LayerConflictException;
 import org.apache.skywalking.oap.server.receiver.runtimerule.cluster.MainRouter;
@@ -1038,9 +1041,25 @@ private HttpResponse doAddOrUpdateLocked(final String catalog, final String name
             // Engine-driven classification — routes via RuleEngineRegistry so a catalog
             // declared on MalRuleEngine.supportedCatalogs (e.g., telegraf-rules) classifies
             // as MAL automatically, no parallel string list to maintain.
-            delta = DSLScriptKey.isMalCatalog(dslManager.getEngineRegistry(), catalog)
-                ? DeltaClassifier.classifyMal(priorContent, content)
-                : DeltaClassifier.classifyLal(priorContent, content);
+            //
+            // Each engine gets its own named branch. This was a MAL/LAL ternary, written when
+            // those were the only two engines, so its else meant "LAL" — and would silently
+            // hand a THIRD engine's rule to the LAL classifier. An unknown catalog cannot reach
+            // here: validate() above rejects it with invalid_catalog using the same
+            // registry lookup (isValidCatalog). So NONE means a catalog whose engine is
+            // registered but has no delta classifier, which today cannot happen and tomorrow
+            // should fail loudly rather than be parsed as LAL.
+            final EngineKind kind = engineKindFor(dslManager.getEngineRegistry(), catalog);
+            if (kind == EngineKind.MAL) {
+                delta = DeltaClassifier.classifyMal(priorContent, content);
+            } else if (kind == EngineKind.LAL) {
+                delta = DeltaClassifier.classifyLal(priorContent, content);
+            } else {
+                log.warn("runtime-rule: catalog {} is served by an engine with no delta "
+                    + "classifier, rule {}", catalog, name);
+                return badRequest("unsupported_engine", catalog, name,
+                    "no delta classifier for the engine serving catalog " + catalog);
+            }
         } catch (final RuntimeException pe) {
             log.warn("runtime-rule: compile_failed during classify for {}/{}: {}",
                 catalog, name, pe.getMessage());
@@ -2433,4 +2452,33 @@ private static JsonObject renderBundledEntry(final DSLRuntimeState local) {
         row.addProperty("pendingUnregister", false);
         return row;
     }
+
+    /** Which DSL owns a catalog, or {@link #NONE} when no engine is registered for it. */
+    enum EngineKind { MAL, LAL, NONE }
+
+    /**
+     * Resolves the engine owning a catalog to a three-valued answer.
+     *
+     * <p>Package-private and extracted so the {@code NONE} case is testable. This used to be a
+     * MAL/LAL ternary whose {@code else} was reached by anything not MAL, so a third engine's
+     * rule would have been handed to the LAL classifier. Callers on the REST path have already
+     * passed {@code validate()}, which rejects an unregistered catalog with
+     * {@code invalid_catalog} using this same registry lookup, so {@code NONE} there means a
+     * registered engine this method does not know — not bad input.
+     *
+     * @param registry the live engine registry
+     * @param catalog  the catalog named in the request
+     * @return which engine owns it, or {@code NONE}
+     */
+    static EngineKind engineKindFor(final RuleEngineRegistry registry, final String catalog) {
+        final RuleEngine<?> engine = registry.forCatalog(catalog);
+        if (engine instanceof MalRuleEngine) {
+            return EngineKind.MAL;
+        }
+        if (engine instanceof LalRuleEngine) {
+            return EngineKind.LAL;
+        }
+        return EngineKind.NONE;
+    }
+
 }
diff --git a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/state/DSLRuntimeState.java b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/state/DSLRuntimeState.java
index f52fb63d14d8..3afb3f1e0cf8 100644
--- a/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/state/DSLRuntimeState.java
+++ b/oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/state/DSLRuntimeState.java
@@ -106,7 +106,7 @@ public SuspendOrigin remove(final SuspendOrigin other) {
     }
 
     /** Coarse hint about whether the bundle's {@link
-     *  org.apache.skywalking.oap.server.core.classloader.RuleClassLoader} has been retired
+     *  org.apache.skywalking.oap.server.core.dsl.classloader.RuleClassLoader} has been retired
      *  and, if so, whether the JVM has confirmed collection. */
     public enum LoaderGc {
         /** The loader is alive, serving active classes. */
diff --git a/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplierTest.java b/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplierTest.java
index 2c519f59c489..82c9fc4086b7 100644
--- a/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplierTest.java
+++ b/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/LalFileApplierTest.java
@@ -210,7 +210,7 @@ void successfulApplyCompilesAndRegistersEveryRule() throws Exception {
         assertNotNull(applied.getRuleClassLoader(),
             "per-file loader must be retained so the dslManager can retire it through the "
                 + "graveyard on unregister");
-        assertEquals(org.apache.skywalking.oap.server.core.classloader.Catalog.LAL,
+        assertEquals(org.apache.skywalking.oap.server.core.dsl.Catalog.LAL,
             applied.getRuleClassLoader().getCatalog());
         assertEquals("multi", applied.getRuleClassLoader().getRule());
         assertEquals("h-ok", applied.getRuleClassLoader().getContentHash());
diff --git a/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplierTest.java b/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplierTest.java
index 66f147557c71..99f13af9a90c 100644
--- a/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplierTest.java
+++ b/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/MalFileApplierTest.java
@@ -118,7 +118,7 @@ void successfulApplyRegistersDerivedMetricNames() throws Exception {
         assertNotNull(applied);
         assertNotNull(applied.getRuleClassLoader(),
             "per-file loader must be retained for graveyard observation");
-        assertEquals(org.apache.skywalking.oap.server.core.classloader.Catalog.OTEL_RULES,
+        assertEquals(org.apache.skywalking.oap.server.core.dsl.Catalog.OTEL_RULES,
             applied.getRuleClassLoader().getCatalog());
         assertEquals("vm", applied.getRuleClassLoader().getRule());
         assertEquals("hashA", applied.getRuleClassLoader().getContentHash());
diff --git a/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleServiceEngineKindTest.java b/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleServiceEngineKindTest.java
new file mode 100644
index 000000000000..d96b65c782bc
--- /dev/null
+++ b/oap-server/server-admin/runtime-rule/src/test/java/org/apache/skywalking/oap/server/receiver/runtimerule/rest/RuntimeRuleServiceEngineKindTest.java
@@ -0,0 +1,104 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.oap.server.receiver.runtimerule.rest;
+
+import java.util.HashMap;
+import org.apache.skywalking.oap.server.receiver.runtimerule.engine.RuleEngineRegistry;
+import org.apache.skywalking.oap.server.receiver.runtimerule.engine.lal.LalRuleEngine;
+import org.apache.skywalking.oap.server.receiver.runtimerule.engine.mal.MalRuleEngine;
+import org.apache.skywalking.oap.server.receiver.runtimerule.state.AppliedRuleScript;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Pins which engine classifies a catalog's rule content.
+ *
+ * <p>This was a MAL/LAL ternary — {@code isMalCatalog(...) ? classifyMal : classifyLal} — written
+ * when MAL and LAL were the only two engines, so its {@code else} genuinely meant LAL. It would
+ * therefore hand a THIRD engine's rule to the LAL classifier.
+ *
+ * <p>Scope, so these assertions are not read as more than they are: on the REST path an
+ * unregistered catalog never reaches this method. {@code RuntimeRuleService.validate} rejects it
+ * with {@code invalid_catalog} using the very same registry lookup. {@code engineKindFor} is a
+ * pure function and its {@code null} behaviour is pinned below as a property of the function, not
+ * as a reachable request. What is genuinely reachable, once a third engine registers, is the last
+ * case: an engine this dispatch does not know.
+ */
+class RuntimeRuleServiceEngineKindTest {
+
+    private static RuleEngineRegistry registryWith(final boolean mal, final boolean lal) {
+        final RuleEngineRegistry registry = new RuleEngineRegistry();
+        // Both constructors only assign their two fields, so a null ModuleManager is safe here:
+        // engineKindFor never calls into the engine, it only asks the registry which type owns
+        // the catalog.
+        if (mal) {
+            registry.register(new MalRuleEngine(new HashMap<String, AppliedRuleScript>(), null));
+        }
+        if (lal) {
+            registry.register(new LalRuleEngine(new HashMap<String, AppliedRuleScript>(), null));
+        }
+        return registry;
+    }
+
+    @Test
+    void aMalCatalogResolvesToMal() {
+        final RuleEngineRegistry registry = registryWith(true, true);
+
+        assertEquals(RuntimeRuleService.EngineKind.MAL,
+            RuntimeRuleService.engineKindFor(registry, "otel-rules"));
+        // Every catalog MalRuleEngine declares must land on MAL, not just the first — that is the
+        // property the registry lookup exists to preserve as catalogs are added.
+        assertEquals(RuntimeRuleService.EngineKind.MAL,
+            RuntimeRuleService.engineKindFor(registry, "meter-analyzer-config"));
+        assertEquals(RuntimeRuleService.EngineKind.MAL,
+            RuntimeRuleService.engineKindFor(registry, "telegraf-rules"));
+        assertEquals(RuntimeRuleService.EngineKind.MAL,
+            RuntimeRuleService.engineKindFor(registry, "log-mal-rules"));
+    }
+
+    @Test
+    void aLalCatalogResolvesToLal() {
+        assertEquals(RuntimeRuleService.EngineKind.LAL,
+            RuntimeRuleService.engineKindFor(registryWith(true, true), "lal"));
+    }
+
+    @Test
+    void anUnregisteredCatalogIsNoneRatherThanLal() {
+        // A property of the function, not a reachable request: validate() rejects an unregistered
+        // catalog before the dispatch runs. Pinned so the dispatch stays total.
+        assertEquals(RuntimeRuleService.EngineKind.NONE,
+            RuntimeRuleService.engineKindFor(registryWith(true, true), "no-such-catalog"));
+        assertEquals(RuntimeRuleService.EngineKind.NONE,
+            RuntimeRuleService.engineKindFor(registryWith(true, true), ""));
+    }
+
+    @Test
+    void anEngineThisDispatchDoesNotKnowIsNoneRatherThanLal() {
+        // The case that is actually reachable, once a third RuleEngine registers: its catalog
+        // passes validate() because forCatalog returns non-null, then matches neither instanceof.
+        // With the old ternary it would have been classified by the LAL parser, silently. The
+        // registry here stands in for that: an engine registered for one DSL, asked about the
+        // other's catalog.
+        assertEquals(RuntimeRuleService.EngineKind.NONE,
+            RuntimeRuleService.engineKindFor(registryWith(true, false), "lal"));
+        assertEquals(RuntimeRuleService.EngineKind.NONE,
+            RuntimeRuleService.engineKindFor(registryWith(false, true), "otel-rules"));
+    }
+}
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/meter/MeterSystem.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/meter/MeterSystem.java
index 4d84de678fb1..0a96f7629e92 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/meter/MeterSystem.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/meter/MeterSystem.java
@@ -40,7 +40,6 @@
 import org.apache.commons.lang3.JavaVersion;
 import org.apache.commons.lang3.SystemUtils;
 import org.apache.skywalking.oap.server.core.UnexpectedException;
-import org.apache.skywalking.oap.server.core.classloader.BytecodeClassDefiner;
 import org.apache.skywalking.oap.server.core.analysis.StreamDefinition;
 import org.apache.skywalking.oap.server.core.analysis.TimeBucket;
 import org.apache.skywalking.oap.server.core.analysis.meter.dynamic.MeterClassPackageHolder;
@@ -54,6 +53,7 @@
 import org.apache.skywalking.oap.server.core.CoreModule;
 import org.apache.skywalking.oap.server.library.module.ModuleManager;
 import org.apache.skywalking.oap.server.library.module.Service;
+import org.apache.skywalking.oap.server.core.dsl.classloader.BytecodeClassDefiner;
 
 /**
  * MeterSystem provides the API way to create {@link MetricsStreamProcessor} rather than manual analysis metrics or OAL
@@ -292,27 +292,12 @@ private <T> void createInternal(final String metricsName,
         }
         final Class targetClass;
         try {
-            // Explicit targetClassLoader — the generated class goes directly into the
-            // per-file RuleClassLoader, not the neighbor class's loader. Two paths:
-            //
-            //   - {@link BytecodeClassDefiner} loaders (the runtime-rule {@code
-            //     RuleClassLoader} is the only known implementor today): hand the loader
-            //     the raw bytecode via its public {@code defineClass(String, byte[])}.
-            //     This sidesteps Javassist's deprecated 2-arg {@code toClass(loader,
-            //     ProtectionDomain)} which reflects into {@code java.lang.ClassLoader.
-            //     defineClass} and requires {@code --add-opens java.base/java.lang} on
-            //     JDK 17+ — a JVM-flag tax we don't want to put on every operator.
-            //
-            //   - Other loaders (legacy callers): keep the 2-arg toClass for back-compat.
-            //     No new constraints on existing static rule paths; they don't use this
-            //     overload anyway, so this branch is effectively dead today and exists as
-            //     a safety net.
-            if (targetClassLoader instanceof BytecodeClassDefiner) {
-                targetClass = ((BytecodeClassDefiner) targetClassLoader)
-                    .defineClass(METER_CLASS_PACKAGE + className, metricsClass.toBytecode());
-            } else {
-                targetClass = metricsClass.toClass(targetClassLoader, null);
-            }
+            // The generated class goes into the per-file RuleClassLoader, not a neighbour's
+            // loader. BytecodeClassDefiner.define owns which of the two definition paths applies and
+            // why; the anchor is only reached when targetClassLoader is null, which this
+            // overload's single caller never does.
+            targetClass = BytecodeClassDefiner.define(
+                metricsClass, targetClassLoader, MeterClassPackageHolder.class);
             AcceptableValue prototype = (AcceptableValue) targetClass.newInstance();
             meterPrototypes.put(metricsName, new MeterDefinition(type, prototype, dataType, true));
             MetricsStreamProcessor.getInstance().create(
@@ -332,11 +317,11 @@ private <T> void createInternal(final String metricsName,
                 meterPrototypes.remove(metricsName);
             }
         } catch (CannotCompileException | IllegalAccessException | InstantiationException
-                 | StorageException | IOException e) {
+                 | StorageException e) {
             // Also roll back on exception paths — an unsuccessful create must not leave a
-            // prototype stranded in the registry. {@link IOException} surfaces from
-            // {@code metricsClass.toBytecode()} when serialising the generated bytes; treat
-            // it the same as a Javassist compile failure so the apply rolls back cleanly.
+            // prototype stranded in the registry. A failure to serialise the generated bytes
+            // arrives here as CannotCompileException, wrapped by BytecodeClassDefiner.define, and is
+            // handled the same way it always was.
             meterPrototypes.remove(metricsName);
             throw new UnexpectedException(e.getMessage(), e);
         }
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/Catalog.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/Catalog.java
similarity index 93%
rename from oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/Catalog.java
rename to oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/Catalog.java
index 3c163c4004cd..680a404df1f1 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/Catalog.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/Catalog.java
@@ -16,9 +16,10 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl;
 
 import lombok.Getter;
+import org.apache.skywalking.oap.server.core.dsl.classloader.DSLClassLoaderManager;
 
 /**
  * Strongly-typed catalog identifier consumed by {@link DSLClassLoaderManager} so the manager's
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslGeneratedFileWriter.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslGeneratedFileWriter.java
index f49ba3d51818..a2bc84ba2794 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslGeneratedFileWriter.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslGeneratedFileWriter.java
@@ -34,6 +34,8 @@
 import javassist.bytecode.MethodInfo;
 import javassist.bytecode.SourceFileAttribute;
 import lombok.extern.slf4j.Slf4j;
+import org.apache.skywalking.oap.server.core.WorkPath;
+import org.apache.skywalking.oap.server.library.util.StringUtil;
 
 /**
  * Emits the artifacts of a generated DSL class: the {@code .class}, the {@code .java} beside it,
@@ -244,4 +246,24 @@ public static void addLocalVariableTable(final CtMethod method,
             log.warn("Failed to add LocalVariableTable: {}", e.getMessage());
         }
     }
+
+    /**
+     * Where a DSL dumps its generated {@code .class} / {@code .java}, or null when it should not.
+     *
+     * <p>Four generators each had their own copy of this env lookup; MAL, LAL and Hierarchy adopt
+     * this one. OAL keeps its own, because its debug flag is settable independently of the
+     * environment variable and two tests rely on that. The kernel already
+     * owns the write ({@link #writeClassFile}, {@link #writeSourceFile}), the file naming
+     * ({@link DslSourceRef#sourceFileOf}) and the sibling codegen switch, so whether and where to
+     * dump is the last part of one story that lived elsewhere.
+     *
+     * @param dslName short DSL name, e.g. {@code mal} — the directory is {@code <dslName>-rt}
+     * @return the directory, or null when {@code SW_DYNAMIC_CLASS_ENGINE_DEBUG} is unset
+     */
+    public static File resolveClassDumpDir(final String dslName) {
+        if (StringUtil.isEmpty(System.getenv("SW_DYNAMIC_CLASS_ENGINE_DEBUG"))) {
+            return null;
+        }
+        return new File(WorkPath.getPath().getParentFile(), dslName + "-rt");
+    }
 }
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslSourceRef.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslSourceRef.java
index e673d94ec2a9..d1293bbf439a 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslSourceRef.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/DslSourceRef.java
@@ -59,6 +59,17 @@
  * pair — it is the join key tying them back together, and what the dsl-debugging API reports so a
  * captured sample names an editable location.
  *
+ * <p><b>One entrance, on purpose — do not add a producer interface.</b> Each DSL converts its own
+ * config into this type at its own call site: MAL from {@code MetricRuleConfig}, LAL from
+ * {@code LALConfig}'s fields, OAL from a {@code SourceLocation}, Hierarchy from a constant plus a
+ * name-to-line map. That looks like four answers to one question, and a shared
+ * {@code sourcePath()/lineNo()} interface has been proposed to unify it. It should not be added:
+ * two of the four cannot implement it. OAL's dispatcher deliberately wants a LINELESS ref, because
+ * one dispatcher spans every metric of a scope, and Hierarchy has no per-rule object to hang an
+ * interface on. The remaining two would gain little, and the escape hatches for the other two
+ * would cost more than the duplication. The narrow entrance below — a file and a line — is the
+ * contract; what each DSL knows about its own rules stays where that knowledge lives.
+ *
  * <p><b>Unresolved lines.</b> A line is normally always available: rules are bound from YAML
  * snakeyaml can re-compose. {@link #UNRESOLVED} is a defensive fallback, deliberately {@code -1}
  * rather than {@code 0}: a silently missing line hides the failure, whereas {@code -1} stays
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/BytecodeClassDefiner.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/BytecodeClassDefiner.java
similarity index 56%
rename from oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/BytecodeClassDefiner.java
rename to oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/BytecodeClassDefiner.java
index 618918f94f2c..fa0f8a1de7c1 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/BytecodeClassDefiner.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/BytecodeClassDefiner.java
@@ -16,7 +16,11 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
+
+import java.io.IOException;
+import javassist.CannotCompileException;
+import javassist.CtClass;
 
 /**
  * Marker contract for class loaders that expose a public {@code defineClass} so generated
@@ -55,4 +59,42 @@ public interface BytecodeClassDefiner {
      * @return the resolved {@link Class} object loaded by this defining loader.
      */
     Class<?> defineClass(String className, byte[] bytecode);
+
+    /**
+     * Loads a generated class, choosing the definition path from the target loader.
+     *
+     * <p>Three call sites did this identically — MAL's and LAL's generators and
+     * {@code MeterSystem} — so a change had to be made three times and the reasoning above was
+     * restated in four places. It lives on this interface rather than in a class of its own
+     * because the whole decision is about whether the loader implements this interface.
+     *
+     * @param ctClass           the generated class, not yet loaded
+     * @param targetClassLoader the loader to define into; null selects the neighbour form, which
+     *                          puts the class in {@code packageAnchor}'s package and loader
+     * @param packageAnchor     a class naming the package to define into when there is no target
+     *                          loader — each DSL keeps its own empty holder for this
+     * @return the loaded class
+     * @throws CannotCompileException if Javassist cannot define it, or if serialising its bytes
+     *                                fails
+     */
+    static Class<?> define(final CtClass ctClass,
+                           final ClassLoader targetClassLoader,
+                           final Class<?> packageAnchor) throws CannotCompileException {
+        if (targetClassLoader == null) {
+            return ctClass.toClass(packageAnchor);
+        }
+        if (targetClassLoader instanceof BytecodeClassDefiner) {
+            try {
+                return ((BytecodeClassDefiner) targetClassLoader)
+                    .defineClass(ctClass.getName(), ctClass.toBytecode());
+            } catch (final IOException e) {
+                // Reported as a compile failure rather than propagated: every caller already
+                // handles CannotCompileException, and failing to serialise bytes this process
+                // just generated is not meaningfully different from a compile failure.
+                throw new CannotCompileException(
+                    "failed to serialise " + ctClass.getName() + " bytes", e);
+            }
+        }
+        return ctClass.toClass(targetClassLoader, null);
+    }
 }
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/ClassLoaderGc.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/ClassLoaderGc.java
similarity index 99%
rename from oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/ClassLoaderGc.java
rename to oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/ClassLoaderGc.java
index 915ae7242013..ee54199dde18 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/ClassLoaderGc.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/ClassLoaderGc.java
@@ -16,8 +16,9 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/DSLClassLoaderManager.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/DSLClassLoaderManager.java
similarity index 99%
rename from oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/DSLClassLoaderManager.java
rename to oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/DSLClassLoaderManager.java
index c63fa5662af7..ba7ad989a0e1 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/DSLClassLoaderManager.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/DSLClassLoaderManager.java
@@ -16,8 +16,9 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Objects;
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/RuleClassLoader.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/RuleClassLoader.java
similarity index 97%
rename from oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/RuleClassLoader.java
rename to oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/RuleClassLoader.java
index 95f1076e689c..31af5647b034 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/RuleClassLoader.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/RuleClassLoader.java
@@ -16,8 +16,9 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.time.LocalDateTime;
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/UnloadProbePayload.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/UnloadProbePayload.java
similarity index 95%
rename from oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/UnloadProbePayload.java
rename to oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/UnloadProbePayload.java
index 0b10381c1b35..7d322a19f3b1 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/classloader/UnloadProbePayload.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/classloader/UnloadProbePayload.java
@@ -16,7 +16,7 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
 /**
  * Bytecode payload for {@link ClassLoaderGc}'s unload-evidence probe. Never instantiated and
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKey.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKey.java
index 9256414b3842..5ff122842027 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKey.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKey.java
@@ -22,7 +22,7 @@
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.ToString;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 
 /**
  * Typed identity for one rule in the DSL debug API. Replaces every
diff --git a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/ClassLoaderGcTest.java b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/ClassLoaderGcTest.java
similarity index 97%
rename from oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/ClassLoaderGcTest.java
rename to oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/ClassLoaderGcTest.java
index 7f6d5f8f01e1..50d82c07ad2a 100644
--- a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/ClassLoaderGcTest.java
+++ b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/ClassLoaderGcTest.java
@@ -16,8 +16,9 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import java.lang.ref.Reference;
 import java.util.Collection;
 import org.junit.jupiter.api.Test;
diff --git a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/DSLClassLoaderManagerTest.java b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/DSLClassLoaderManagerTest.java
similarity index 97%
rename from oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/DSLClassLoaderManagerTest.java
rename to oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/DSLClassLoaderManagerTest.java
index abac015e685f..58762967c224 100644
--- a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/DSLClassLoaderManagerTest.java
+++ b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/DSLClassLoaderManagerTest.java
@@ -16,8 +16,9 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import java.util.Optional;
 import org.junit.jupiter.api.Test;
 
diff --git a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/RuleClassLoaderTest.java b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/RuleClassLoaderTest.java
similarity index 97%
rename from oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/RuleClassLoaderTest.java
rename to oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/RuleClassLoaderTest.java
index 1a03400c03ad..c59c86d351ab 100644
--- a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/classloader/RuleClassLoaderTest.java
+++ b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/classloader/RuleClassLoaderTest.java
@@ -16,8 +16,9 @@
  *
  */
 
-package org.apache.skywalking.oap.server.core.classloader;
+package org.apache.skywalking.oap.server.core.dsl.classloader;
 
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
diff --git a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/GateHolderTest.java b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/GateHolderTest.java
index ce490a467e6e..4b09a541ecab 100644
--- a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/GateHolderTest.java
+++ b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/GateHolderTest.java
@@ -18,7 +18,7 @@
 
 package org.apache.skywalking.oap.server.core.dsl.debug;
 
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
diff --git a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKeyTest.java b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKeyTest.java
index c38fbf179085..4d286e4b80e1 100644
--- a/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKeyTest.java
+++ b/oap-server/server-core/src/test/java/org/apache/skywalking/oap/server/core/dsl/debug/RuleKeyTest.java
@@ -20,7 +20,7 @@
 
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.Map;
-import org.apache.skywalking.oap.server.core.classloader.Catalog;
+import org.apache.skywalking.oap.server.core.dsl.Catalog;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;