mock methods in same class

I am using Mockito to mock a method in the same class for which I am writing test. I have seen other answers on SO (Mocking method in the same class), but probably I am misunderstanding them, since I running into issues.

 class Temp() {

    public boolean methodA(String param) {

         try {

             if(methodB(param))
                   return true;

             return false;
         } catch (Exception e) {
               e.printStackTrace();
         }
    }
 }

My Test method:

 @Test
 public void testMethodA() {

    Temp temp = new Temp();
    Temp spyTemp = Mockito.spy(temp);

    Mockito.doReturn(true).when(spyTemp).methodB(Mockito.any()); 
    boolean status = temp.methodA("XYZ");

    Assert.assertEquals(true, status);
 }

I however get the expection printed out because definition of methodB gets executed. My understanding is definition of methodB would get mocked by using spyTemp. However that does not appear to be the case.

Can someone please explain where I am going wrong?