Hi,
the following code generates a null pointer exception in the TreeCache class when I try to persist the treecache:

Map map = new HashMap();
map.put(MAP_KEY_PM, pm);
map.put(MAP_KEY_DESTINATION, stsDestination);
treeCache.put(
 getPathToPMIDNode(pm.getId()), // path to node
 map); // map

;
while if I try the following:

treeCache.put(
 getPathToPMIDNode(pm.getId()), // path to node
 MAP_KEY_PM,
 pm);
treeCache.put(
 getPathToPMIDNode(pm.getId()), // path to node
 MAP_KEY_DESTINATION,
 stsDestination);

it works perfectly well.
Here is the stack trace:

RuntimeMBeanException: null Cause: RuntimeMBeanException: null Cause: org.jboss.util.NestedRuntimeException: - nested throwable: (java.lang.NullPointe
rException)
[...]
Caused by: RuntimeMBeanException: null Cause: org.jboss.util.NestedRuntimeException: - nested throwable: (java.lang.NullPointerException)
 at org.jboss.mx.interceptor.ReflectedDispatcher.handleInvocationExceptions(ReflectedDispatcher.java:162)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:149)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:80)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:72)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:249)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:644)
 at javax.management.MBeanServerInvocationHandler$InvokeAction.perform(MBeanServerInvocationHandler.java:322)
 at javax.management.MBeanServerInvocationHandler.invoke(MBeanServerInvocationHandler.java:140)
 at $Proxy164.put(Unknown Source)
 at apackage.TreeCacheHandler.addMessage(TreeCacheHandler.java:267)
 at apackage.MasterMessageQueue.scheduleMessage(MasterMessageQueue.java:284)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:324)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:141)
 ... 46 more
Caused by: org.jboss.util.NestedRuntimeException: - nested throwable: (java.lang.NullPointerException)
 at org.jboss.cache.TreeCache.invokeMethod(TreeCache.java:3107)
 at org.jboss.cache.TreeCache.put(TreeCache.java:1670)
 at org.jboss.cache.TreeCache.put(TreeCache.java:1654)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:324)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:141)
 ... 60 more
Caused by: java.lang.NullPointerException
 at org.jboss.cache.TreeCache.invokeMethod(TreeCache.java:3102)
 ... 67 more

Here is my configuration of the environment

<attribute name="CacheLoaderClass">org.jboss.cache.loader.JDBCCacheLoader</attribute>
 <attribute name="CacheLoaderShared">true</attribute>
 <attribute name="CacheLoaderPreload">/</attribute>
 <attribute name="CacheLoaderFetchTransientState">true</attribute>
 <attribute name="CacheLoaderFetchPersistentState">false</attribute>
 <attribute name="CacheLoaderConfig">
 cache.jdbc.table.name=mmq_schedule
 cache.jdbc.table.create=true
 cache.jdbc.table.drop=false
 cache.jdbc.fqn.column=fqn
 cache.jdbc.fqn.type=varchar(255)
 cache.jdbc.node.column=node
 cache.jdbc.node.type=longvarbinary
 cache.jdbc.parent.column=parent
 cache.jdbc.datasource=java:/DefaultDS
 </attribute>

where the DefaultDS is mapped to a HSQLDB database.
The JBoss version is 4.0.2 and the treecache version is:

Manifest-Version: 1.0
Specification-Title: JBoss
Created-By: 1.4.2_05-b04 (Sun Microsystems Inc.)
Specification-Version: 4.0.2
Implementation-Vendor-Id: http://www.jboss.org/
Implementation-URL: http://www.jboss.org/
Ant-Version: Apache Ant 1.6.2
Main-Class: org.jboss.cache.Version
Implementation-Title: JBossCache
Specification-Vendor: JBoss (http://www.jboss.org/)
Implementation-Version: 4.0.2 (build: CVSTag=JBoss_4_0_2 date=20050502
 2023)
JBossCache-Version: 1.2
Implementation-Vendor: JBoss Inc.

Can anybody help me to solve this problem?
Thank you.