Example of Garbage Collection

import java.io.*;
import java.lang.*;
class GC
{
public static void main(String s[])
{
Runtime r=Runtime.getRuntime();
System.out.println("Total Memory:" +r.totalMemory());
System.out.println("Free Momery before allocation:" +r.freeMemory());
String str[] = new String[20];

for(int i=0;i<20;i++)
{
str[i]=new String("String Object No. "+i);
System.out.println(str[i]);
}
System.out.println("Free Momery after allocation:" +r.freeMemory());
for(int i=0;i<20;i++)
str[i]=null;
r.gc();
System.out.println("Free Momery after Garbage Collection:" +r.freeMemory());
}
}