I trying to add a RequestHandler . but its not work. and I don’t know why, plz help me . thanks. this is my custom handler public class TestHandler extends RequestHandler { @Override protected void processRequest(IMxRuntimeRequest arg0, IMxRuntimeResponse arg1, String arg2) throws Exception { // TODO Auto-generated method stub logger.info(arg0.getHeader("accept")); } } this is my java action , and I already set up Runtime op as “After startup” import com.mendix.core.Core; public class JS_RequestHandler extends CustomJavaAction<java.lang.Boolean> { public JS_RequestHandler(IContext context) { super(context); } @java.lang.Override public java.lang.Boolean executeAction() throws Exception { // BEGIN USER CODE try { Core.addRequestHandler("rest/", new TestHandler()); return true; } catch (Exception e) { throw new com.mendix.systemwideinterfaces.MendixRuntimeException("Java action was not implemented"); } // END USER CODE } ……some thing }