1 Reply Latest reply on Jun 14, 2004 12:29 PM by Ben Wang

    TreeCacheAop Map field support and java.util.ConcurrentModi

    gabrieli Newbie

      I'm a new user of TreeCacheAop (v1.01). My cached (POJO) class is constructed of a private HashMap member and a private reference to itself (same class) [to build a tree-like object hierarchy/graph].
      While loading (putObject) my objects' hierarchy to the TreeCacheAop I'm getting the following exception:

      Exception in thread "main" java.util.ConcurrentModificationException
      at java.util.HashMap$HashIterator.nextEntry(HashMap.java(Compiled Code))
      at java.util.HashMap$KeyIterator.next(HashMap.java:894)
      at org.jboss.cache.aop.TreeCacheAop._removeObject(TreeCacheAop.java:548)
      at org.jboss.cache.aop.TreeCacheAop._removeObject(TreeCacheAop.java:533)
      at org.jboss.cache.aop.TreeCacheAop.removeObject(TreeCacheAop.java:503)
      at org.jboss.cache.aop.TreeCacheAop.handleObjectGraph(TreeCacheAop.java:366)
      at org.jboss.cache.aop.TreeCacheAop._putObject(TreeCacheAop.java:209)
      at org.jboss.cache.aop.TreeCacheAop.putObject(TreeCacheAop.java:133)
      at org.jboss.cache.aop.TreeCacheAop.putObject(TreeCacheAop.java:114)
      at org.amir.TestDeviceCache.test(TestDeviceCache.java:245)
      at org.amir.TestDeviceCache.main(TestDeviceCache.java:327)

      It seems that the source of the exception is internal to the TreeCacheAop. I've located the 'iterator” that caused the exception:

      ~TreeCacheAop.java:548 method: "_removeObject":

      protected Object _removeObject(Fqn fqn, boolean removeCacheInterceptor) throws Exception

      } else if (Map.class.isAssignableFrom(clazz)) {
      Map values = get(fqn).getChildren();
      if (values != null) {
      for (Iterator i = values.keySet().iterator(); i.hasNext();) {

      Object key = i.next(); // EXCEPTION HERE (line 548)

      _removeObject(new Fqn(fqn, key), removeCacheInterceptor);
      } else if (Collection.class.isAssignableFrom(clazz)) {
      Map values = get(fqn).getChildren();
      int size = values == null ? 0 : values.size();
      for (int i = 0; i < size; i++) {
      _removeObject(new Fqn(fqn, new Integer(i)), removeCacheInterceptor);

      Am I using the TreeCacheAop (Map support) wrong or is it something else?

      My POJO class is:

      public class Device {

      public String name=null;
      public Device parent=null;
      public Map attributes=null;

      public Device(){}
      public String getName() {
      return name;
      public Device getParent() {
      return parent;
      public void setName(String name) {
      this.name = name;
      public void setParent(Device device) {
      parent = device;
      public void setAttributes(Map attrbiutesMap)
      this.attributes = attrbiutesMap;

      public Object getProperty(String propName)
      Object obj = attributes.get(propName);
      if (obj==null && parent != null){
      obj = parent.getProperty(propName);

      return obj;


      The class is complied with aopc complier and is working great until its HashMap is filled and the object is begin referenced by another.