mockito -using one of the values from list of values to compare in matcher

or does not have a three-argument overload. (See docs.) If your code compiles, you may be importing a different or method than org.mockito.AdditionalMatchers.or.

or(or(eq("amol84"),eq("arpan")),eq("juhi")) should work.

You might also try the isOneOf Hamcrest matcher, accessed through the argThat Mockito matcher:

when(authService.isAuthenticated(argThat(isOneOf("amol84", "arpan", "juhi"))))
    .thenReturn(true);

You could define separate answers:

when(authService.isAuthenticated(eq("amol84"))).thenReturn(true);
when(authService.isAuthenticated(eq("arpan"))).thenReturn(true);
when(authService.isAuthenticated(eq("juhi"))).thenReturn(true);