Java program to perform garbage collection


Levels of difficulty: / perform operation:

This program performs garbage collection. Free memory in java virtual machine is printed and then garbage collection is done using gc method of RunTime class, freeMemory method returns amount of free memory in jvm, getRunTime method is used to get reference of current RunTime object.

This java program

import java.util.*;
class GarbageCollection {
	public static void main(String s[]) throws Exception {
		Runtime rs =  Runtime.getRuntime();
		System.out.println("Free memory in JVM before Garbage Collection = "+rs.freeMemory());
		rs.gc();
		System.out.println("Free memory in JVM after Garbage Collection = "+rs.freeMemory());
	}
}


Output

Obviously the amount of available after garbage collection will be different on your computer. Numbers are not important, what is important is that amount of memory available is more than before. You can use this code in your program or projects which uses large amount of memory or where frequently new objects are created but are required for a short span of time.