当jdk 14启用 --enable-preview 时，复杂的类 watch/trace出错

[hengyunabc]

java.lang.UnsupportedOperationException: class redefinition failed: attempted to change the class NestHost, NestMembers, or Record attribute
        at java.instrument/sun.instrument.InstrumentationImpl.retransformClasses0(Native Method)
        at java.instrument/sun.instrument.InstrumentationImpl.retransformClasses(InstrumentationImpl.java:167)
        at com.taobao.arthas.core.advisor.Enhancer.enhance(Enhancer.java:371)
        at com.taobao.arthas.core.command.monitor200.EnhancerCommand.enhance(EnhancerCommand.java:149)
        at com.taobao.arthas.core.command.monitor200.EnhancerCommand.process(EnhancerCommand.java:96)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.process(AnnotatedCommandImpl.java:82)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.access$100(AnnotatedCommandImpl.java:18)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:111)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:108)
        at com.taobao.arthas.core.shell.system.impl.ProcessImpl$CommandProcessTask.run(ProcessImpl.java:385)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
        at java.base/java.lang.Thread.run(Thread.java:832)

asm已升级为最新版本 9.0，并且使用了最新的API ASM9 。

---

复现demo：

public class BBB {
    public String test() {
        return "hello";
    }
}

public class FFF {
    public String test() {
        
        Thread t = new Thread(new Runnable() {

            @Override
            public void run() {
                System.err.println("ttt");
            }
            
        });
        t.start();
        return "hello";
    }
}

import java.io.IOException;

public class TTT {
    
    public static void main(String[] args) throws  IOException {
        
        System.err.println(new FFF());
        System.err.println(new BBB());
        System.in.read();
        
    }

}

• 建立上面三个文件
• 使用jdk 14来编译：jdk-14.0.2.jdk/Contents/Home/bin/javac --enable-preview --release 14 ./*.java
• 启动： jdk-14.0.2.jdk/Contents/Home/bin/java --enable-preview TTT
• 启动 arthas attach
• watch BBB test ，这个是正常结果
• watch FFF test ，会抛出上面的异常

[hengyunabc]

另外，在一个复杂的应用上，使用jdk 14，启用了 --enable-preview ，在watch时抛出下面的异常：

2020-09-24 15:38:41 [arthas-command-execute] INFO  c.t.arthas.core.advisor.Enhancer -enhance matched classes: [class com.aliyun.apsaradb.perfv4.store.dbdao.LogDbDao$$EnhancerBySpringCGLIB$$16733ee1, class com.aliyun.apsaradb.perfv4.store.dbdao.LogDbDao]
2020-09-24 15:38:41 [arthas-command-execute] ERROR c.t.arthas.core.advisor.Enhancer -Enhancer error, matchingClasses: [class com.aliyun.apsaradb.perfv4.store.dbdao.LogDbDao$$EnhancerBySpringCGLIB$$16733ee1, class com.aliyun.apsaradb.perfv4.store.dbdao.LogDbDao]
java.lang.ClassFormatError: null
        at java.instrument/sun.instrument.InstrumentationImpl.retransformClasses0(Native Method)
        at java.instrument/sun.instrument.InstrumentationImpl.retransformClasses(InstrumentationImpl.java:167)
        at com.taobao.arthas.core.advisor.Enhancer.enhance(Enhancer.java:371)
        at com.taobao.arthas.core.command.monitor200.EnhancerCommand.enhance(EnhancerCommand.java:149)
        at com.taobao.arthas.core.command.monitor200.EnhancerCommand.process(EnhancerCommand.java:96)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.process(AnnotatedCommandImpl.java:82)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl.access$100(AnnotatedCommandImpl.java:18)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:111)
        at com.taobao.arthas.core.shell.command.impl.AnnotatedCommandImpl$ProcessHandler.handle(AnnotatedCommandImpl.java:108)
        at com.taobao.arthas.core.shell.system.impl.ProcessImpl$CommandProcessTask.run(ProcessImpl.java:385)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
        at java.base/java.lang.Thread.run(Thread.java:832)

可以发现有spring aop增强的类： EnhancerBySpringCGLIB ，但和这个类无关。

因为，如果直接 watch 这个spring aop类，结果是正常的。

如果打开 options disable-sub-class true，再次 watch com.aliyun.apsaradb.perfv4.store.dbdao.LogDbDao ，则只会匹配到一个类（没有spring aop类），还是会报错。

本地未能复现，也许和上面的错误类似。

[hengyunabc]

另外，加上-noverify参数，仍然会出错。

[hengyunabc]

options dump true ，打开dump开关，检查下生成的增强的字节码，发现

public class FFF
  minor version: 0
  major version: 49

再检查下代码，是这个commit引起的： 25c5fb7 ，关联issue: #1223

[hengyunabc]

原因是 .class 文件里的 java version是两部分组成的，高位是 minor ,通常是0， 低位是 major。 当启动 --enable-preview 时，编译出来的 .class 文件 的 minor version 是 65535 。 之前的代码只是简单的认为 classNode.version 就是 major version，导致出错。

[hengyunabc]

修复包测试： arthas-bin.zip