docs: public V remove(Object key) {
          V retval=get(key);
          try {
              MethodCall call=new MethodCall(REMOVE, key);
              disp.callRemoteMethods(null, call, call_options);
          }
          catch(Exception e) {
              throw new RuntimeException("remove(" + key + ") failed", e);
          }
          return retval;
      }