During processing of a push request, the ICEfaces CharacterEncodingHandler class tries to change the characterEncoding. In a WebSphere environment, this call throws an IllegalStateException

Caused by: java.lang.IllegalStateException: This method must not be called after the HTTP-Body was accessed !
        at com.ibm.ws.portletcontainer.core.impl.PortletRequestImpl.setCharacterEncoding(PortletRequestImpl.java:1103)
        at org.portletfaces.bridge.context.ExternalContextImpl.setRequestCharacterEncoding(ExternalContextImpl.java:791)
        at org.icefaces.impl.util.CharacterEncodingHandler.setCharacterEncoding(CharacterEncodingHandler.java:76)
        at org.icefaces.impl.util.CharacterEncodingHandler.isResourceRequest(CharacterEncodingHandler.java:65)
        at javax.faces.application.ResourceHandlerWrapper.isResourceRequest(ResourceHandlerWrapper.java:68)
        at javax.faces.application.ResourceHandlerWrapper.isResourceRequest(ResourceHandlerWrapper.java:68)
        at javax.faces.application.ResourceHandlerWrapper.isResourceRequest(ResourceHandlerWrapper.java:68)
        at org.portletfaces.bridge.BridgeImpl.doFacesRequest(BridgeImpl.java:506)

There are some additional comments here:
https://issues.apache.org/jira/browse/PORTLETBRIDGE-48