I have 2 object :

Object A {
 private String ax;
 private String bx;
}

Object B {
 private A ax;
 private String bx;
}

How I parse :

A objA = A
        .builder()
        .ax(ax_val)
        .bx(bx_val)
        .build();
B data = B
        .builder()
        .objA(objA)
        .ax(ax_val)
        .build();
String requestBody = gson.toJson(data);

Object receiver in rest :

public class Receiver {
    private A objA;
    private String ax;
    private String bx;
}

Rest :

public ResponseEntity<HashMap<String, Object>> getObj (@Validated @RequestBody Receiver inData) throws Exception {
        HashMap<String, Object> hResult = new HashMap<>();
        hResult = service.getData(inData);
        return ResponseEntity.ok(hResult);
}

I already parsed B as json as for requirement to send to API , but the API can’t map the A inside B even if I already matched the name as well. I want to get A.ax value. Any idea how to solve this ? I’m using gson for JSON parser.
Thank you