private ImmutableSet<String> collectThrownCheckedExceptions() {
    Set<String> exceptions = new HashSet<>(2);
    Environment env = protoclass().environment();
    for (TypeMirror thrown : ((ExecutableElement) element).getThrownTypes()) {
      if (env.isCheckedException(thrown)) {
        exceptions.add(thrown.toString());
      }
    }
    return ImmutableSet.copyOf(exceptions);
  }
Initialized Validates things that were not validated otherwise
@param instantiationCreator can instantiate encodings
value-processor/src/org/immutables/value/processor/meta/ValueAttribute.java