How to initialize ThreadLocal objects in Java

Question

I\'m having an issue where I\'m creating a ThreadLocal and initializing it with new ThreadLocal . The problem is, I really conceptually just want a persistent list that last

Answer 1

Your solution is fine. A little simplification:

private static Whatever getMyVariable() 
{
    Whatever w = myThreadLocalVariable.get();
    if(w == null) 
        myThreadLocalVariable.set(w=new Whatever());
    return w; 
} 

In Java 8, we are able to do:

ThreadLocal> myThreadLocal = ThreadLocal.withInitial(ArrayList::new);

which uses the Supplier functional interface.