上机执行下列程序（ 学习·Runtime类），注意观察程序的

public class Test{
    public static void main(String args[]){
        Runtime runtime=Runtime.getRuntime();
        long free = runtime.freeMemory();
        System.out,println("Java虚拟机可用空闲内存"+free+“bytes”);
        long total = runtime.totalMemory();
        System.out.println("Java虚拟机占用总内存"+total+“bytes”);
        long n1 = System.currentTimeMillis();
        for(){
            int j=2;
            for(int i=1;i<=100;i++){
                  if(;j<=i/2;j++){
                    if(i%j==0)break;
            }
            if(j>1/2)System.out.print(" "+i);
        }
        long n2 = System.currentTimeMillis();
        System.out,printf("\n循环用时："+(n2-n1)+"毫秒\n");
        free = runtime.freeMemory();
        System.out.println("Java虚拟机可用空闲内存"+free+"bytes");
        total = runtime.totalMemory();
        System.out.println("Java虚拟机占用总内存 "+total+" bytes");
    }
}