How to view your JVM default settings

cat Test.java 

public class Test {
   public static void main(String[] args) {
        for (;;) {
        }

   } 

}

javac Test.java
java -XX:+PrintCommandLineFlags Test
you should get something like this:
-XX:InitialHeapSize=67108864 -XX:MaxHeapSize=1073741824 -XX:+PrintCommandLineFlags -XX:+UseParallelGC