Which Java Collections are synchronized(thread safe), which are not?

Question

Which Java Collections are synchronized, which are not?

Example: HashSet is not synchronized

Answer 1

Easy answer: not a single implementation of Collection is synchronized because synchronized is not a class property, it is only applicable to methods and blocks.

I guess, you want to know which implementations are thread safe, which classes from the java collection framework can safely be used in a multithreaded environment.

The information is always included in the javadoc (like here: Arraylist - which is not thread safe)