Study tips 1Z0-804

Which two are true?

Which class(es) safely protects the doIt () method from concurrent thread access?

what threading problem does the program suffer?

Which class implements IdGenerator in a thread-safe manner, so that no threads can get a duplicate id value current access?

What is the result?

Which fragment puts a key/value pair in partList without the responsibility of overwriting an existing key?

What is the likely result?

Which line of code, inserted inside the increment () method, will increment the value of c?

Which two changes make the program work correctly?

How many Threads are created when passing task to an Executor instance?