The number of threads garbage collectors use in the garbage collection stop-the-world pauses determine the number of threads to use based on the maximum size of the Java heap. The flag -XX:UseDynamicNumberOfGCThreads is now true (enabled) by default.

This improves startup time and reduces resource usage particularly for Java applications run with a small Java heap.

If you experience performance reductions particularly on applications that use a small amount of Java heap, you can disable this new behavior by specifying -XX:- UseDynamicNumberOfGCThreads on the command line.