Only initialise extension methods once.

Author: graemerocher

grails-core/src/main/groovy/org/codehaus/groovy/grails/commons/DefaultGrailsApplication.java

@@ -685,7 +685,11 @@ public void initialise() {
         initialised = true;
     }
 
-    protected void initialiseGroovyExtensionModules() {
+    private static boolean extensionMethodsInitialized = false;
+    protected static void initialiseGroovyExtensionModules() {
+        if(extensionMethodsInitialized) return;
+
+        extensionMethodsInitialized = true;
         Map<CachedClass, List<MetaMethod>> map = new HashMap<CachedClass, List<MetaMethod>>();
 
         ClassLoader classLoader = Thread.currentThread().getContextClassLoader();