diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/util/CompositeFormat.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/util/CompositeFormat.java
index 333496529..f17021792 100644
--- a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/util/CompositeFormat.java
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/util/CompositeFormat.java
@@ -64,8 +64,11 @@ public static NumberFormat getDefaultNumberFormat(final Locale locale) {
      */
     public static void parseAndIgnoreWhitespace(final String source,
                                                 final ParsePosition pos) {
+        final int startIndex = pos.getIndex();
         parseNextCharacter(source, pos);
-        pos.setIndex(pos.getIndex() - 1);
+        if (pos.getIndex() > startIndex) {
+            pos.setIndex(pos.getIndex() - 1);
+        }
     }
 
     /**
@@ -88,7 +91,7 @@ public static char parseNextCharacter(final String source,
              } while (Character.isWhitespace(c) && index < n);
              pos.setIndex(index);
 
-             if (index < n) {
+             if (!Character.isWhitespace(c)) {
                  ret = c;
              }
          }
@@ -172,8 +175,7 @@ public static boolean parseFixedstring(final String source,
 
         final int startIndex = pos.getIndex();
         final int endIndex = startIndex + expected.length();
-        if (startIndex >= source.length() ||
-            endIndex > source.length() ||
+        if (endIndex > source.length() ||
             source.substring(startIndex, endIndex).compareTo(expected) != 0) {
             // set index back to start, error index should be the start index
             pos.setIndex(startIndex);
diff --git a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/linear/RealMatrixFormatAbstractTest.java b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/linear/RealMatrixFormatAbstractTest.java
index e5a230222..8030cc78c 100644
--- a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/linear/RealMatrixFormatAbstractTest.java
+++ b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/linear/RealMatrixFormatAbstractTest.java
@@ -359,4 +359,20 @@ public void testForgottenSuffix() {
         Assert.assertNull("Should not parse <"+source+">", realMatrixFormat.parse(source, pos));
         Assert.assertEquals(9, pos.getErrorIndex());
     }
+
+    @Test
+    public void testForgottenSuffixAtEndOfInput() {
+        ParsePosition pos = new ParsePosition(0);
+        final String source = "{{1}";
+        Assert.assertNull("Should not parse <"+source+">", realMatrixFormat.parse(source, pos));
+        Assert.assertEquals(4, pos.getErrorIndex());
+    }
+
+    @Test
+    public void testParseEmptySuffixAtEndOfInput() {
+        ParsePosition pos = new ParsePosition(0);
+        final RealMatrix parsed = new RealMatrixFormat("", "", "", "", "; ", ", ").parse("1, 2; 3, 4", pos);
+        Assert.assertEquals(MatrixUtils.createRealMatrix(new double[][] {{1, 2}, {3, 4}}), parsed);
+        Assert.assertEquals(10, pos.getIndex());
+    }
 }
diff --git a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/util/ComplexFormatAbstractTest.java b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/util/ComplexFormatAbstractTest.java
index 37cffdfd1..3a05cad35 100644
--- a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/util/ComplexFormatAbstractTest.java
+++ b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/util/ComplexFormatAbstractTest.java
@@ -459,4 +459,18 @@ public void testParseRejectsInvalidGroupingSeparators() {
             }
         }
     }
+
+    @Test
+    public void testParseRejectsTrailingCharacter() {
+        final ComplexFormat format = new ComplexFormat();
+        final String[] invalid = {"2i", "1x", "1 +"};
+        for (final String source : invalid) {
+            try {
+                format.parse(source);
+                Assert.fail("Expected parsing to reject: " + source);
+            } catch (MathParseException expected) {
+                // Expected.
+            }
+        }
+    }
 }