How to conseme service exposed by SAP GATEWAY(OData) in PO ( java stack )

Hi All,

My requirment is I want to consume service exposed by GW server in my PO server using EJB program.

There is SSO enabled betweeb PO and GATEWAY.

I have create a ejb which is generation a get service call.

URL gatewayServiceUrl = new URL("http://192.168.1.55:8020/sap/opu/odata/sap/ZGW_BPM_TEST_SERVICE_SRV/GetData1Set?$filter=age eq '50'");

HttpURLConnection connection = (HttpURLConnection) gatewayServiceUrl.openConnection();

connection.setRequestMethod("GET");

connection.connect();

for above code I am getting HTTP 400

How can I call a service for a perticular user for which SSO is configured between PO and Gateway.

Please provide step, configuration detail, code snippet.