difference in behavior when reflect is specified in PowerMock Accepting?

Question

I am a Java beginner.

As you can see in the source code below, when I searched the sample code of URL class Mock on the net, There are cases where there is no reflect and cases where there is reflect. How is the behavior different in each case?

What does a block-like description like {String.class} mean?

URL mockedURL = PowerMockito.mock(URL); 
PowerMockito.when(mockedURL.openConnection()).thenReturn(mockedConnection);

// not reflect case
PowerMockito.whenNew(URL.class).withArguments(Mockito.anyString()).thenReturn(mockedURL);

// reflect case
PowerMockito.whenNew(URL.class.getConstructor(new Class<?>[]{String.class})).withArguments(Mockito.anyString()).thenReturn(mockedURL);

Answer 1

 PowerMockito.when(mockedURL.openConnection()).thenReturn(mockedConnection);

This defines that when the openConnection() method is called on the mockedURL object, the value mockedConnection is returned instead (and not the real code is called). This syntax/approach is defined/used in the "Mockito" library as well.

 PowerMockito.whenNew(URL.class).withArguments(Mockito.anyString())

This will be used when you create the URL object with a string as an argument. Using PowerMockito.whenNew() with a class argument allows you to use withAnyArguments() to mock any constructor of that class, not just a specific one.

 PowerMockito.whenNew(URL.class.getConstructor(new Class<?>[]{String.class}))

This is used to select the specific constructor. In this case it's the one with the String argument. So when you write new URL("some string") , this mock is used.

 new Class<?>[]{String.class}

This is just an array with values declaration like any other. It's like writing

new int[] {4, 6, 10}

Only that the type is Class<?> and the values are one String.class object.