What is Java Heap Space in Java virtual Machine JVM?

Java heap is the heap size allocated to JVM applications which takes care of the new objects being created. If the objects being created exceed the heap size, it will throw an error saying memoryOutof Bound
Java's default heap size limit is 128MB.
It is possible to increase heap size allocated by the Java Virtual Machine (JVM) by using command line options.
Following are few options available to change Heap Size.

-Xms        set initial Java heap size
-Xmx        set maximum Java heap size
-Xss        set java thread stack size