Class replacement need also StringManager.stringsMemoryOffset.

src/de/inetsoftware/jwebassembly/module/FunctionManager.java

@@ -124,6 +124,21 @@ class FunctionManager {
         getOrCreate( name ).state = State.Written;
     }
 
+    /**
+     * Same like markAsNeeded but it will replace the function name if already registered.
+     * 
+     * @param name
+     *            the function name
+     */
+    void markAsNeededAndReplaceIfExists( SyntheticFunctionName name ) {
+        FunctionState state = states.get( name );
+        if( state != null ) {
+            states.remove( name );
+            states.put( name, state );
+        }
+        markAsNeeded( name );
+    }
+
     /**
      * Mark a function as used/called and return the real name if there is an alias.
      * 

src/de/inetsoftware/jwebassembly/module/ModuleGenerator.java

@@ -474,6 +474,7 @@ public class ModuleGenerator {
             } else {
                 FunctionName name = new FunctionName( method );
                 if( "java/lang/Class.typeTableMemoryOffset()I".equals( name.signatureName ) ) {
+                    strings.getStringConstantFunction(); // we will need also the string constant function for the Class Name, in the other case a program with only new Object().getClass().getName() will fail to compile 
                     return types.getTypeTableMemoryOffsetFunctionName().getCodeBuilder( watParser );
                 }
                 throw new WasmException( "Abstract or native method can not be used: " + name.signatureName, -1 );

src/de/inetsoftware/jwebassembly/module/StringManager.java

@@ -83,13 +83,13 @@ public class StringManager extends LinkedHashMap<String, Integer> {
         if( stringMemoryOffset < 0 ) {
             // register the function stringsMemoryOffset() as synthetic function
             stringMemoryOffset = 0;
-            FunctionName offsetFunction =
+            WatCodeSyntheticFunctionName offsetFunction =
                             new WatCodeSyntheticFunctionName( "de/inetsoftware/jwebassembly/module/StringManager", "stringsMemoryOffset", "()I", "", null, ValueType.i32 ) {
                                 protected String getCode() {
                                     return "i32.const " + stringMemoryOffset;
                                 }
                             };
-            functions.markAsNeeded( offsetFunction );
+            functions.markAsNeededAndReplaceIfExists( offsetFunction );
         }
 
         return STRING_CONSTANT_FUNCTION;