org.springframework.dao.InvalidDataAccessApiUsageException: MOVED redirection loop detected. Node redis://10.2.26.106:6379 has further redirect to redis://xxx:6379; nested exception is org.redisson.client.RedisException: MOVED redirection loop detected. Node redis://10.2.26.106:6379 has further redirect to redis://xxx:6379

The Java programming language allows threads to access shared variables (§17.1).
As a rule, to ensure that shared variables are consistently and reliably updated, a
thread should ensure that it has exclusive use of such variables by obtaining a lock
that, conventionally, enforces mutual exclusion for those shared variables.
The Java programming language provides a second mechanism, volatile fields,
that is more convenient than locking for some purposes

在java中,可以由不同的线程共享一个变量.
线程必须通过获得锁来保证共享的变量可以被可靠和一致的更新.
简单来说,就是使用mutual的排他性来获取这个特性
java除了通过锁,还有另外一个机制来访问和更新共享变量,这就是volatile fields.
在某些情况下volatile field会比锁更加方便

If a program is not correctly synchronized, then three types of problems can appear:
visibility, ordering and atomicity.

class BadlyOrdered {
    boolean a = false;
    boolean b = false;

    void threadOne() {
        a = true;
        b = true;
    }

    boolean threadTwo() {
        boolean r1 = b; // sees true
        boolean r2 = a; // sees false
        return r1 && !r2; // returns true
    }
}

#include <pthread.h>
#include <semaphore.h>
#include <stdio.h>

// Set either of these to 1 to prevent CPU reordering
#define USE_CPU_FENCE              0
#define USE_SINGLE_HW_THREAD       0  // Supported on Linux, but not Cygwin or PS3

#if USE_SINGLE_HW_THREAD
#include <sched.h>
#endif


//-------------------------------------
//  MersenneTwister
//  A thread-safe random number generator with good randomness
//  in a small number of instructions. We'll use it to introduce
//  random timing delays.
//-------------------------------------
#define MT_IA  397
#define MT_LEN 624

class MersenneTwister
{
    unsigned int m_buffer[MT_LEN];
    int m_index;

public:
    MersenneTwister(unsigned int seed);
    // Declare noinline so that the function call acts as a compiler barrier:
    unsigned int integer() __attribute__((noinline));
};

MersenneTwister::MersenneTwister(unsigned int seed)
{
    // Initialize by filling with the seed, then iterating
    // the algorithm a bunch of times to shuffle things up.
    for (int i = 0; i < MT_LEN; i++)
        m_buffer[i] = seed;
    m_index = 0;
    for (int i = 0; i < MT_LEN * 100; i++)
        integer();
}

unsigned int MersenneTwister::integer()
{
    // Indices
    int i = m_index;
    int i2 = m_index + 1; if (i2 >= MT_LEN) i2 = 0; // wrap-around
    int j = m_index + MT_IA; if (j >= MT_LEN) j -= MT_LEN; // wrap-around

    // Twist
    unsigned int s = (m_buffer[i] & 0x80000000) | (m_buffer[i2] & 0x7fffffff);
    unsigned int r = m_buffer[j] ^ (s >> 1) ^ ((s & 1) * 0x9908B0DF);
    m_buffer[m_index] = r;
    m_index = i2;

    // Swizzle
    r ^= (r >> 11);
    r ^= (r << 7) & 0x9d2c5680UL;
    r ^= (r << 15) & 0xefc60000UL;
    r ^= (r >> 18);
    return r;
}


//-------------------------------------
//  Main program, as decribed in the post
//-------------------------------------
sem_t beginSema1;
sem_t beginSema2;
sem_t endSema;

int X, Y;
int r1, r2;

void *thread1Func(void *param)
{
    MersenneTwister random(1);
    for (;;)
    {
        sem_wait(&beginSema1);  // Wait for signal
        while (random.integer() % 8 != 0) {}  // Random delay

        // ----- THE TRANSACTION! -----
        X = 1;
#if USE_CPU_FENCE
        asm volatile("mfence" ::: "memory");  // Prevent CPU reordering
#else
        asm volatile("" ::: "memory");  // Prevent compiler reordering
#endif
        r1 = Y;

        sem_post(&endSema);  // Notify transaction complete
    }
    return NULL;  // Never returns
};

void *thread2Func(void *param)
{
    MersenneTwister random(2);
    for (;;)
    {
        sem_wait(&beginSema2);  // Wait for signal
        while (random.integer() % 8 != 0) {}  // Random delay

        // ----- THE TRANSACTION! -----
        Y = 1;
#if USE_CPU_FENCE
        asm volatile("mfence" ::: "memory");  // Prevent CPU reordering
#else
        asm volatile("" ::: "memory");  // Prevent compiler reordering
#endif
        r2 = X;

        sem_post(&endSema);  // Notify transaction complete
    }
    return NULL;  // Never returns
};

int main()
{
    // Initialize the semaphores
    sem_init(&beginSema1, 0, 0);
    sem_init(&beginSema2, 0, 0);
    sem_init(&endSema, 0, 0);

    // Spawn the threads
    pthread_t thread1, thread2;
    pthread_create(&thread1, NULL, thread1Func, NULL);
    pthread_create(&thread2, NULL, thread2Func, NULL);

#if USE_SINGLE_HW_THREAD
    // Force thread affinities to the same cpu core.
    cpu_set_t cpus;
    CPU_ZERO(&cpus);
    CPU_SET(0, &cpus);
    pthread_setaffinity_np(thread1, sizeof(cpu_set_t), &cpus);
    pthread_setaffinity_np(thread2, sizeof(cpu_set_t), &cpus);
#endif

    // Repeat the experiment ad infinitum
    int detected = 0;
    for (int iterations = 1; ; iterations++)
    {
        // Reset X and Y
        X = 0;
        Y = 0;
        // Signal both threads
        sem_post(&beginSema1);
        sem_post(&beginSema2);
        // Wait for both threads
        sem_wait(&endSema);
        sem_wait(&endSema);
        // Check if there was a simultaneous reorder
        if (r1 == 0 && r2 == 0)
        {
            detected++;
            printf("%d reorders detected after %d iterations\n", detected, iterations);
        }
    }
    return 0;  // Never returns
}

## 然后编译
 gcc -O2   reorder.cpp  -o reorder

## 执行
./reorder

$ microk8s inspect

WARNING:  This machine's hostname contains capital letters and/or underscores. 
	  This is not a valid name for a Kubernetes node, causing node registration to fail.
	  Please change the machine's hostname or refer to the documentation for more details:

$ hostname
dai-MS-7B89

$ hostnamectl
 Static hostname: dai-MS-7B89
       Icon name: computer-desktop
         Chassis: desktop
      Machine ID: d55c62a250474c459bda9aecc21307a7
         Boot ID: e97354108f364004a0775ce12cc57d98
Operating System: Ubuntu 22.04 LTS                  
          Kernel: Linux 5.15.0-56-generic
    Architecture: x86-64
 Hardware Vendor: Micro-Star International Co., Ltd.
  Hardware Model: MS-7B89

sudo hostnamectl set-hostname  myhost

javap -s java.lang.String
Compiled from "String.java"
public final class java.lang.String implements java.io.Serializable, java.lang.Comparable<java.lang.String>, java.lang.CharSequence {
  static final boolean COMPACT_STRINGS;
    descriptor: Z
  public static final java.util.Comparator<java.lang.String> CASE_INSENSITIVE_ORDER;
    descriptor: Ljava/util/Comparator;
  static final byte LATIN1;
    descriptor: B
  static final byte UTF16;
    descriptor: B
  public java.lang.String();
    descriptor: ()V



  public java.lang.String(byte[], int, int, int);
    descriptor: ([BIII)V

  public java.lang.String(byte[], int);
    descriptor: ([BI)V

  public java.lang.String(byte[], int, int, java.lang.String) throws java.io.UnsupportedEncodingException;
    descriptor: ([BIILjava/lang/String;)V

 
}

git clone https://github.com/apache/tomcat

sudo apt install ant

cp build.properties.default  build.properties

<javac srcdir="java" destdir="${tomcat.classes}"
           debug="${compile.debug}"                      <--!     这里会有compile.debug 环境变量 ->
           deprecation="${compile.deprecation}"
           release="${compile.release}"
           encoding="ISO-8859-1"
           includeAntRuntime="true" >
      <!-- Uncomment this to show unchecked warnings:
      <compilerarg value="-Xlint:unchecked"/>

# ----- Build control flags -----
compile.debug=true

ant

{source_code}/output/build/bin

./startup.sh 
Using CATALINA_BASE:   /home/dai/tomcat/output/build
Using CATALINA_HOME:   /home/dai/tomcat/output/build
Using CATALINA_TMPDIR: /home/dai/tomcat/output/build/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /home/dai/tomcat/output/build/bin/bootstrap.jar:/home/dai/tomcat/output/build/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Tomcat started.

ps aux | grep tomcat


/usr/bin/java -Djava.util.logging.config.file=/home/dai/tomcat/output/build/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED -classpath /home/dai/tomcat/output/build/bin/bootstrap.jar:/home/dai/tomcat/output/build/bin/tomcat-juli.jar -Dcatalina.base=/home/dai/tomcat/output/build -Dcatalina.home=/home/dai/tomcat/output/build -Djava.io.tmpdir=/home/dai/tomcat/output/build/temp org.apache.catalina.startup.Bootstrap start

/usr/bin/java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=8000   -Djava.util.logging.config.file=/home/dai/tomcat/output/build/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED -classpath /home/dai/tomcat/output/build/bin/bootstrap.jar:/home/dai/tomcat/output/build/bin/tomcat-juli.jar -Dcatalina.base=/home/dai/tomcat/output/build -Dcatalina.home=/home/dai/tomcat/output/build -Djava.io.tmpdir=/home/dai/tomcat/output/build/temp org.apache.catalina.startup.Bootstrap start

jdb  -attach  8000 -sourcepath /home/dai/tomcat/java/

### 在  org.apache.catalina.startup.Bootstrap.main 打断点
main[1] stop in   org.apache.catalina.startup.Bootstrap.main
Deferring breakpoint org.apache.catalina.startup.Bootstrap.main.
It will be set after the class is loaded.
#### 使用run开始执行
main[1] run

Breakpoint hit: "thread=main", org.apache.catalina.startup.Bootstrap.main(), line=442 bci=0
442            synchronized (daemonLock) {

main[1] list
438         * @param args Command line arguments to be processed
439         */
440        public static void main(String args[]) {
441    
442 =>         synchronized (daemonLock) {
443                if (daemon == null) {
444                    // Don't set daemon until init() has completed
445                    Bootstrap bootstrap = new Bootstrap();
446                    try {
447                        bootstrap.init();
main[1] 

http-nio-8080-exec-1[1] where
  [1] HelloWorldExample.doGet (HelloWorldExample.java:41)
  [2] jakarta.servlet.http.HttpServlet.service (HttpServlet.java:705)
  [3] jakarta.servlet.http.HttpServlet.service (HttpServlet.java:814)
  [4] org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (ApplicationFilterChain.java:223)
  [5] org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain.java:158)
  [6] org.apache.tomcat.websocket.server.WsFilter.doFilter (WsFilter.java:53)
  [7] org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (ApplicationFilterChain.java:185)
  [8] org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain.java:158)
  [9] org.apache.catalina.filters.HttpHeaderSecurityFilter.doFilter (HttpHeaderSecurityFilter.java:126)
  [10] org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (ApplicationFilterChain.java:185)
  [11] org.apache.catalina.core.ApplicationFilterChain.doFilter (ApplicationFilterChain.java:158)
  [12] org.apache.catalina.core.StandardWrapperValve.invoke (StandardWrapperValve.java:177)
  [13] org.apache.catalina.core.StandardContextValve.invoke (StandardContextValve.java:97)
  [14] org.apache.catalina.authenticator.AuthenticatorBase.invoke (AuthenticatorBase.java:542)
  [15] org.apache.catalina.core.StandardHostValve.invoke (StandardHostValve.java:119)
  [16] org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:92)
  [17] org.apache.catalina.valves.AbstractAccessLogValve.invoke (AbstractAccessLogValve.java:690)
  [18] org.apache.catalina.core.StandardEngineValve.invoke (StandardEngineValve.java:78)
  [19] org.apache.catalina.connector.CoyoteAdapter.service (CoyoteAdapter.java:357)
  [20] org.apache.coyote.http11.Http11Processor.service (Http11Processor.java:400)
  [21] org.apache.coyote.AbstractProcessorLight.process (AbstractProcessorLight.java:65)
  [22] org.apache.coyote.AbstractProtocol$ConnectionHandler.process (AbstractProtocol.java:859)
  [23] org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun (NioEndpoint.java:1,734)
  [24] org.apache.tomcat.util.net.SocketProcessorBase.run (SocketProcessorBase.java:52)
  [25] org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1,191)
  [26] org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:659)
  [27] org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run (TaskThread.java:61)
  [28] java.lang.Thread.run (Thread.java:833)

initialize:108, TomcatWebServer (org.springframework.boot.web.embedded.tomcat)
<init>:104, TomcatWebServer (org.springframework.boot.web.embedded.tomcat)
getTomcatWebServer:440, TomcatServletWebServerFactory (org.springframework.boot.web.embedded.tomcat)
getWebServer:193, TomcatServletWebServerFactory (org.springframework.boot.web.embedded.tomcat)
createWebServer:178, ServletWebServerApplicationContext (org.springframework.boot.web.servlet.context)
onRefresh:158, ServletWebServerApplicationContext (org.springframework.boot.web.servlet.context)
refresh:545, AbstractApplicationContext (org.springframework.context.support)
refresh:143, ServletWebServerApplicationContext (org.springframework.boot.web.servlet.context)
refresh:755, SpringApplication (org.springframework.boot)
refresh:747, SpringApplication (org.springframework.boot)
refreshContext:402, SpringApplication (org.springframework.boot)
run:312, SpringApplication (org.springframework.boot)
main:22, Application

getLanguagesAllList:35, CommonController (com.patpat.mms.mdp.base.core.rest.controller)
invoke:-1, CommonController$$FastClassBySpringCGLIB$$2cf69542 (com.patpat.mms.mdp.base.core.rest.controller)
invoke:218, MethodProxy (org.springframework.cglib.proxy)
invokeJoinpoint:779, CglibAopProxy$CglibMethodInvocation (org.springframework.aop.framework)
proceed:163, ReflectiveMethodInvocation (org.springframework.aop.framework)
proceed:750, CglibAopProxy$CglibMethodInvocation (org.springframework.aop.framework)
proceed:88, MethodInvocationProceedingJoinPoint (org.springframework.aop.aspectj)
doAround:27, AbstractLogAspect (com.patpat.marketing.common.aspect.log)
invoke0:-1, NativeMethodAccessorImpl (jdk.internal.reflect)
invoke:62, NativeMethodAccessorImpl (jdk.internal.reflect)
invoke:43, DelegatingMethodAccessorImpl (jdk.internal.reflect)
invoke:566, Method (java.lang.reflect)
invokeAdviceMethodWithGivenArgs:644, AbstractAspectJAdvice (org.springframework.aop.aspectj)
invokeAdviceMethod:633, AbstractAspectJAdvice (org.springframework.aop.aspectj)
invoke:70, AspectJAroundAdvice (org.springframework.aop.aspectj)
proceed:186, ReflectiveMethodInvocation (org.springframework.aop.framework)
proceed:750, CglibAopProxy$CglibMethodInvocation (org.springframework.aop.framework)
invoke:95, ExposeInvocationInterceptor (org.springframework.aop.interceptor)
proceed:186, ReflectiveMethodInvocation (org.springframework.aop.framework)
proceed:750, CglibAopProxy$CglibMethodInvocation (org.springframework.aop.framework)
intercept:692, CglibAopProxy$DynamicAdvisedInterceptor (org.springframework.aop.framework)
getLanguagesAllList:-1, CommonController$$EnhancerBySpringCGLIB$$cea69971 (com.patpat.mms.mdp.base.core.rest.controller)
invoke0:-1, NativeMethodAccessorImpl (jdk.internal.reflect)
invoke:62, NativeMethodAccessorImpl (jdk.internal.reflect)
invoke:43, DelegatingMethodAccessorImpl (jdk.internal.reflect)
invoke:566, Method (java.lang.reflect)
doInvoke:190, InvocableHandlerMethod (org.springframework.web.method.support)
invokeForRequest:138, InvocableHandlerMethod (org.springframework.web.method.support)
invokeAndHandle:105, ServletInvocableHandlerMethod (org.springframework.web.servlet.mvc.method.annotation)
invokeHandlerMethod:878, RequestMappingHandlerAdapter (org.springframework.web.servlet.mvc.method.annotation)
handleInternal:792, RequestMappingHandlerAdapter (org.springframework.web.servlet.mvc.method.annotation)
handle:87, AbstractHandlerMethodAdapter (org.springframework.web.servlet.mvc.method)
doDispatch:1040, DispatcherServlet (org.springframework.web.servlet)
doService:943, DispatcherServlet (org.springframework.web.servlet)
processRequest:1006, FrameworkServlet (org.springframework.web.servlet)
doPost:909, FrameworkServlet (org.springframework.web.servlet)
service:652, HttpServlet (javax.servlet.http)
service:883, FrameworkServlet (org.springframework.web.servlet)
service:733, HttpServlet (javax.servlet.http)
internalDoFilter:227, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilter:53, WsFilter (org.apache.tomcat.websocket.server)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:100, RequestContextFilter (org.springframework.web.filter)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:93, FormContentFilter (org.springframework.web.filter)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:97, WebMvcMetricsFilter (org.springframework.boot.actuate.metrics.web.servlet)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:201, CharacterEncodingFilter (org.springframework.web.filter)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
invoke:202, StandardWrapperValve (org.apache.catalina.core)
invoke:97, StandardContextValve (org.apache.catalina.core)
invoke:542, AuthenticatorBase (org.apache.catalina.authenticator)
invoke:143, StandardHostValve (org.apache.catalina.core)
invoke:92, ErrorReportValve (org.apache.catalina.valves)
invoke:78, StandardEngineValve (org.apache.catalina.core)
service:357, CoyoteAdapter (org.apache.catalina.connector)
service:374, Http11Processor (org.apache.coyote.http11)
process:65, AbstractProcessorLight (org.apache.coyote)
process:893, AbstractProtocol$ConnectionHandler (org.apache.coyote)
doRun:1707, NioEndpoint$SocketProcessor (org.apache.tomcat.util.net)
run:49, SocketProcessorBase (org.apache.tomcat.util.net)
runWorker:1128, ThreadPoolExecutor (java.util.concurrent)
run:628, ThreadPoolExecutor$Worker (java.util.concurrent)
run:61, TaskThread$WrappingRunnable (org.apache.tomcat.util.threads)
run:834, Thread (java.lang)

doService:911, DispatcherServlet (org.springframework.web.servlet)
processRequest:1006, FrameworkServlet (org.springframework.web.servlet)
doPost:909, FrameworkServlet (org.springframework.web.servlet)
service:652, HttpServlet (javax.servlet.http)
service:883, FrameworkServlet (org.springframework.web.servlet)
service:733, HttpServlet (javax.servlet.http)
internalDoFilter:227, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilter:53, WsFilter (org.apache.tomcat.websocket.server)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:100, RequestContextFilter (org.springframework.web.filter)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:93, FormContentFilter (org.springframework.web.filter)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:97, WebMvcMetricsFilter (org.springframework.boot.actuate.metrics.web.servlet)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:201, CharacterEncodingFilter (org.springframework.web.filter)
doFilter:119, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:189, ApplicationFilterChain (org.apache.catalina.core)
doFilter:162, ApplicationFilterChain (org.apache.catalina.core)
invoke:202, StandardWrapperValve (org.apache.catalina.core)
invoke:97, StandardContextValve (org.apache.catalina.core)
invoke:542, AuthenticatorBase (org.apache.catalina.authenticator)
invoke:143, StandardHostValve (org.apache.catalina.core)
invoke:92, ErrorReportValve (org.apache.catalina.valves)
invoke:78, StandardEngineValve (org.apache.catalina.core)
service:357, CoyoteAdapter (org.apache.catalina.connector)
service:374, Http11Processor (org.apache.coyote.http11)
process:65, AbstractProcessorLight (org.apache.coyote)
process:893, AbstractProtocol$ConnectionHandler (org.apache.coyote)
doRun:1707, NioEndpoint$SocketProcessor (org.apache.tomcat.util.net)
run:49, SocketProcessorBase (org.apache.tomcat.util.net)
runWorker:1128, ThreadPoolExecutor (java.util.concurrent)
run:628, ThreadPoolExecutor$Worker (java.util.concurrent)
run:61, TaskThread$WrappingRunnable (org.apache.tomcat.util.threads)
run:834, Thread (java.lang)

 $  java --list-modules
...
jdk.attach@17.0.5
jdk.charsets@17.0.5
jdk.compiler@17.0.5
...

vim com/Hello.java

package com;
public  class Hello{
        public static void main(String [] argc){

                System.out.print(argc.length);

        }
}

java  --module   jdk.compiler/com.sun.tools.javac.Main  com/Hello.java

$tree com
com
├── Hello.class
└── Hello.java

$ java com.Hello
0

returned error: Code: 999, e.displayText() = DB::Exception: Cannot allocate block number in ZooKeeper: Coordination::Exception: xid equal to close_xid (Session expired)