Taking ThreadCritical lock is not necessary while compare-and-swap can do the work.

original:
  new_entry = ClassLoader::create_class_path_entry(_path, &_st, false, CHECK_NULL);
  {
    ThreadCritical tc;
    if (_resolved_entry == NULL) {
      _resolved_entry = new_entry;
      return new_entry;
    }
  }

with CAS

  new_entry = ClassLoader::create_class_path_entry(_path, &_st, false, CHECK_NULL);
  if (Atomic::cmpxchg_ptr(NULL, &_resolved_entry, new_entry) == NULL) {
    return new_entry;
  }