@Test
  public void testWrap_registerSecondWrapperForEncryptOnly_throws() throws Exception {
    assertThrows(
        GeneralSecurityException.class,
        () -> {
          MutablePrimitiveRegistry.globalInstance()
              .registerPrimitiveWrapper(
                  new PrimitiveWrapper<Mac, EncryptOnly>() {
                    @Override
                    public EncryptOnly wrap(PrimitiveSet<Mac> primitiveSet) {
                      return null;
                    }

                    @Override
                    public Class<EncryptOnly> getPrimitiveClass() {
                      return EncryptOnly.class;
                    }

                    @Override
                    public Class<Mac> getInputPrimitiveClass() {
                      return Mac.class;
                    }
                  });
        });
  }
Returns the type URL that identifies the key type of keys managed by this KeyManager.
java_src/src/test/java/com/google/crypto/tink/RegistryTest.java