code runtime class methods

package funds;

public class RuntimeDemo {
    public static void main(String arg[])
    {
        Runtime r=Runtime.getRuntime();
        System.out.println(r.totalMemory());
        System.out.println(r.freeMemory());
        for(int i=0; i<100;i++)
        {
            java.util.Date d=new java.util.Date();
            d=null;
        }
        System.out.println(r.freeMemory());
        r.gc();
        System.out.println(r.freeMemory());
    }
}
output:
2031616
1877944
1877944
1933320