diff --git a/findbugs/src/java/edu/umd/cs/findbugs/util/ClassName.java b/findbugs/src/java/edu/umd/cs/findbugs/util/ClassName.java
index 0712dfa25e..f6fd05ef64 100644
--- a/findbugs/src/java/edu/umd/cs/findbugs/util/ClassName.java
+++ b/findbugs/src/java/edu/umd/cs/findbugs/util/ClassName.java
@@ -217,6 +217,7 @@ public static boolean isAnonymous(String className) {
                 if(!Character.isDigit(className.charAt(i))) {
                     return false;
                 }
+                i++;
             }
             return true;
         }