System

package com.qf.demo2;

public class SystemDemo2 {

    public static void main(String[] args) {
    
        Runtime runtime = Runtime.getRuntime();
        System.out.println(runtime.freeMemory());
        System.gc();// 将垃圾回收器运行起来了 , 并且请理了无用内存空间
                // gc 促进垃圾回收器来
        System.out.println(runtime.freeMemory());
    }
}