static new HashMap<S, Class> findClass_fullName_cache;

// returns null on not found
// this is the simple version that is not case-tolerant
static Class findClass_fullName(String name) {
  synchronized(findClass_fullName_cache) {
    if (findClass_fullName_cache.containsKey(name))
      ret findClass_fullName_cache.get(name);
      
    Class c;
    try {
      c = Class.forName(name);
    } catch (ClassNotFoundException e) {
      c = null;
    }
    findClass_fullName_cache.put(name, c);
    ret c;
  }
}

Began life as a copy of #1001137