SimpleCredentialsSupport implements CredentialsSupport { @Override @NotNull public Set<Class> getCredentialClasses() { return ImmutableSet.<Class>of(SimpleCredentials.class); } private  SimpleCredentialsSupport(); static CredentialsSupport getInstance(); @Override @NotNull Set<Class> getCredentialClasses(); @Override @Nullable String getUserId(@NotNull Credentials credentials); @Override @NotNull Map<String, ?> getAttributes(@NotNull Credentials credentials); @Override boolean setAttributes(@NotNull Credentials credentials, @NotNull Map<String, ?> attributes);  }
@Test public void testGetCredentialClasses() { Set<Class> supported = credentialsSupport.getCredentialClasses(); assertNotNull(supported); assertEquals(1, supported.size()); assertEquals(SimpleCredentials.class, supported.iterator().next()); }