Lazy initialization of "static" fields should be "synchronized" - How to fix it

Question

I am trying to fix an issue which says Lazy initialization of "static" fields should be "synchronized" suggested by findbug.This link suggests that either I have to make the field variable volatile or make the initialization block synchronized. Which way is better? What are pros and cons of each approach?

Answer 1

There is no better.

There are simply a few different patterns how to solve this problem. See here for a complete discussion of that topic.

In that sense: for a newbie doing first steps, simply go with a synchronized method. For "professional" use - see the above link; and determine which of the solutions given there best fits your needs.

Answer 2

In your example you should use synchronized because volatile does not guarantee atomicity. If you use volatile you can initialize several instances of the object.