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

Example of Inside Heap :

public class TestMemory 
{
	public static void main(String [] args) 
	{
		int mb = 1024*1024;
		
		//Getting the runtime reference from system
		Runtime runtime =Runtime.getRuntime();
		System.out.println("##### Heap utilization statistics [MB] #####");

		//Print used memory
		System.out.println("Used Memory:" + (runtime.totalMemory() -
		 runtime.freeMemory()) / mb);

		//Print free memory
		System.out.println("Free Memory:" + runtime.freeMemory()
		 / mb);

		//Print total available memory
		System.out.println("Total Memory:" + runtime.totalMemory()
		 / mb);

		//Print Maximum available memory
		System.out.println("Max Memory:" + runtime.maxMemory() / mb);
	}
}

Output: