curl -O <https://alibaba.github.io/arthas/arthas-boot.jar> java -jar arthas-boot.jar

java -jar arthas-boot.jar -h

java -jar arthas-boot.jar --repo-mirror aliyun --use-http

https://archiva-maven-storage-prod.oss-cn-beijing.aliyuncs.com/repository/jcenter/com/taobao/arthas/arthas-packaging/3.5.4/arthas-packaging-3.5.4-bin.zip%3B?Expires=1637823771&OSSAccessKeyId=LTAIfU51SusnnfCC&Signature=CAlIjIvMl4kh09oMtff%2FBgxyG2U%3D

java -jar arthas-boot.jar

unzip -d /root/app/arthas arthas-packaging-3.5.4-bin.zip

rm -rf ~/.arthas/
rm -rf ~/logs/arthas

curl -O <https://alibaba.github.io/arthas/arthas-demo.jar>

java -jar arthas-demo.jar

[ERROR] The telnet port 3658 is used by process 10472 instead of target process 284, you will connect to an unexpected process.
[ERROR] 1. Try to restart arthas-boot, select process 10472, shutdown it first with running the 'stop' command.
[ERROR] 2. Or try to stop the existing arthas instance: java -jar arthas-client.jar 127.0.0.1 3658 -c "stop"
[ERROR] 3. Or try to use different telnet port, for example: java -jar arthas-boot.jar --telnet-port 9998 --http-port -1

java -jar arthas-boot.jar --telnet-port 9998 --http-port -1

package demo;import java.util.ArrayList;import java.util.List;import java.util.Random;import java.util.concurrent.TimeUnit;public class MathGame {    private static Random random = new Random();        //用于统计生成的不合法变量的个数    public int illegalArgumentCount = 0;    public static void main(String[] args) throws InterruptedException {        MathGame game = new MathGame();        //死循环，每过1秒调用1次下面的方法(不是开启一个线程)        while (true) {            game.run();            TimeUnit.SECONDS.sleep(1);        }    }    //分解质因数    public void run() throws InterruptedException {        try {            //随机生成一个整数，有可能正，有可能负            int number = random.nextInt()/10000;            //调用方法进行质因数分解            List<Integer> primeFactors = primeFactors(number);            //打印结果            print(number, primeFactors);        } catch (Exception e) {            System.out.println(String.format("illegalArgumentCount:%3d, ", illegalArgumentCount) + e.getMessage());        }    }        //打印质因数分解的结果    public static void print(int number, List<Integer> primeFactors) {        StringBuffer sb = new StringBuffer(number + "=");        for (int factor : primeFactors) {            sb.append(factor).append('*');        }        if (sb.charAt(sb.length() - 1) == '*') {            sb.deleteCharAt(sb.length() - 1);        }        System.out.println(sb);    }    //计算number的质因数分解    public List<Integer> primeFactors(int number) {        //如果小于2，则抛出异常，并且计数加1        if (number < 2) {            illegalArgumentCount++;            throw new IllegalArgumentException("number is: " + number + ", need >= 2");        }       //用于保存每个质数        List<Integer> result = new ArrayList<Integer>();        //分解过程，从2开始看能不能整除        int i = 2;        while (i <= number) {  //如果i大于number就退出循环            //能整除，则i为一个因数，number为整除的结果再继续从2开始除            if (number % i == 0) {                result.add(i);                number = number / i;                i = 2;            } else {                i++;  //否则i++            }        }        return result;    }}

jad demo.MathGame

watch demo.MathGame primeFactors returnObj

sysprop | grep java

sysprop | grep java -n

thread | grep system -m 10

sysprop

sysprop java.version

sysprop user.country
user.country=US


sysprop user.country CN
Successfully changed the system property.
user.country=CN

sysenv

sysenv USER

vmoption

vmoption HeapDumpAfterFullGC

vmoption HeapDumpAfterFullGC true

getstatic demo.MathGame random

http://commons.apache.org/proper/commons-ognl/language-guide.html

ognl '@java.lang.System@out.println("hello")'

ognl '@demo.MathGame@random'

ognl '#value1=@System@getProperty("java.home"), #value2=@System@getProperty("java.runtime.name"), {#value1, #value2}'

sc demo.*

sc -d demo.MathGame

sc -df demo.MathGame

mc /data/helloworld.java

mc -d /data/output /data/helloworld.java

public class MathGame {      public static void main(String[] args) throws InterruptedException {         MathGame game = new MathGame();         while (true) {             game.run();             TimeUnit.SECONDS.sleep(1);             // 这个不生效，因为代码一直跑在 while里             System.out.println("在 main 函数中添加");         }     }      public void run() throws InterruptedException {         // 这个生效，因为run()函数每次都可以完整结束         System.out.println("在 run 函数中添加");         try {             int number = random.nextInt();             List<Integer> primeFactors = primeFactors(number);             print(number, primeFactors);         } catch (Exception e) {             System.out.println(String.format("illegalArgumentCount:%3d, ", illegalArgumentCount) + e.getMessage());         }     } }

1. 使用jad反编译demo.MathGame输出到/data/MathGame.java
 jad --source-only demo.MathGame > /data/MathGame.java


 2.按上面的代码编辑完毕以后，使用mc内存中对新的代码编译
 mc /data/MathGame.java -d /data


 3.使用redefine命令加载新的字节码
 redefine /data/demo/MathGame.class