------------- PersistentFacesState.java

package com.icesoft.faces.webapp.xmlhttp

public class PersistentFacesState implements Serializable {
    private static InheritableThreadLocal localInstance = new InheritableThreadLocal() {
            protected Object childValue(Object parentValue) {
                if (parentValue == null) {
                    return parentValue;
                }
                PersistentFacesState state = (PersistentFacesState)parentValue;
                return state.isInheritable() ? state : null;
            }
    };

    public boolean isInheritable() {
        String value =            facesContext.getExternalContext().getInitParameter("InheritableThreadLocalExcludeFilter");
        if (value == null) {
            return true;
        }
        StackTraceElement[] elements = Thread.currentThread().getStackTrace();
        String[] classNames = value.split(";");
        String rhsClassName;
        for (int i = 0; i < classNames.length; ++i) {
            rhsClassName =  classNames[i];
            for (int j = 0; j < elements.length; ++j) {
                StackTraceElement e = elements[j];
                String lhsClassName = e.getClassName();
                if (lhsClassName.equals(rhsClassName)) {
                    return false;
                }
            }
        }
        return true;
    }


------------- web.xml

  <context-param>
    <param-name>InheritableThreadLocalExcludeFilter</param-name>
    <param-value>net.sf.ehcache.CacheManager$1;java.util.TimerThread;com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread;net.sf.ehcache.store.DiskStore$SpoolAndExpiryThread</param-value>
  </context-param>