Reports static variables being lazily initialized
in an non-thread-safe manner. Lazy initialization of static variables should be done
in an appropriate synchronization construct, to prevent different threads from
performing conflicting initialization.
If applicable, quick-fix is suggested
which introduces static holder pattern described in
http://en.wikipedia.org/wiki/Initialization_on_demand_holder_idiom
where the JVM guarantees thread-safety of such initializations.