@@ -0,0 +1,423 @@
+package nxt.http.websocket;%0A%0Aimport org.json.simple.JSONObject;%0Aimport org.json.simple.JSONStreamAware;%0A%0Apublic abstract class RPCCall %7B%0A  %0A    private String identifier;%0A%0A    public RPCCall(String identifier) %7B%0A        this.identifier = identifier;%0A    %7D%0A    %0A    public String getIdentifier() %7B%0A        return identifier;%0A    %7D%0A    %0A    public abstract JSONStreamAware call(JSONObject arguments) throws Exception;%0A    %0A%7D%0A

Add RPCCall base class