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Docker starts the springboot project and reports java version error

I use the following dockerfile to generate a image call userservice
FROM java:8-alpine
COPY ./userservice.jar /tmp/userservice.jar
ENTRYPOINT java -jar /tmp/userservice.jar
then I use the following command to run container
docker run --name userservice_container userservice
But the terminal prompts that the java version does not match，as follows:
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/imortal/UserApplication has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:151)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:46)
at org.springframework.boot.loader.Launcher.launch(Launcher.java:107)
at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88)
So I went to check the compiled bytecode version, it is indeed 52, I don’t know why this error is still reported
javap -verbose .\UserApplication.class
public class com.imortal.UserApplication
minor version: 0
major version: 52
flags: (0x0021) ACC_PUBLIC, ACC_SUPER
this_class: #2 //
com/imortal/UserApplication
super_class: #4 // java/lang/Object
interfaces: 0, fields: 0, methods: 2, attributes: 2

Use a docker image that has a compatible jdk version, so that it doesn't create any conflict with all the microservices that you are having. This issue probably is occuring because one of your microservices is build on some other jdk version.

Can't run JAR files because of outdated JRE but updating it does nothing

I tried to open the jar with "java -jar blah.jar".
this is the outcome:
java -jar Desktop/lambertone2.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: main/Main has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)
at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:56) .
I went to Oracle site to download the latest JRE but it doesn't change anything.
All this happened some day ago where the update section of java told me to erase java because it was obsolete, so i removed it and reinstalled it.
if i use the command java --version it says me that the command is unsupported.
if i use javac --version it says that it is version 10.

RabbitMq and Spring Boot 1.5.8 error java.lang.ClassNotFoundException: reactor.io.codec.Codec

Currently I use spring boot 1.5.8 and I want to use rabbitmq with my websocket.
The following code is my configuration of websocket
#Override
public void configureMessageBroker(MessageBrokerRegistry config) {
config
.enableStompBrokerRelay("/topic", "/queue", "/exchange")
.setRelayHost("localhost")
.setRelayPort(5672)
.setClientLogin("guest")
.setClientPasscode("guest")
.setSystemHeartbeatSendInterval(5000);
}
I add to my gradle config the following dependencies
compile "org.springframework.boot:spring-boot-starter-websocket"
compile("io.projectreactor:reactor-net:2.0.5.RELEASE")
compile("io.projectreactor:reactor-core:2.0.5.RELEASE")
compile("io.netty:netty-all:4.0.33.Final")
Spring boot generate the following stack error
Caused by: java.lang.NoClassDefFoundError: reactor/io/codec/Codec
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.springframework.messaging.simp.stomp.StompBrokerRelayMessageHandler.startInternal(StompBrokerRelayMessageHandler.java:388)
at org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.start(AbstractBrokerMessageHandler.java:164)
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:175)
... 17 common frames omitted
Caused by: java.lang.ClassNotFoundException: reactor.io.codec.Codec
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 32 common frames omitted
I don't know what I'm doing wrong. Any ideas?
I follow the ideas given by http://djeison.me/2017/11/04/spring-websocket-rabbitmq/
And also have the same problem as Spring security 4.0.1 and Spring 4.2.0.RC1 stompBrokerRelayMessageHandler bean error with RabbitMQ

Similar issue resolved on GitHub: https://github.com/zyro23/grails-spring-websocket/issues/26

I have a very rare situation. I will explain it.
I use IntelliJ as my principal IDE for java development. When I configure the gradle plugin with the right panel, I always use the button for refresh dependencies. The strange situation here was that when I run spring boot with bootRun inside IntelliJ, it always generate the same error as the question said. I tried the last resource that was to bootRepackage the jar. Incredible, that was the solution. After the bootRepackage, IntelliJ recognize the new class reactor.io.codec.Codec.
So if you use IntelliJ as your main IDE, try to repackage and after that maybe the error was gone.

Error java.lang.ClassNotFoundException: org.slf4j.LoggerFactory when trying to execute the jar

When I try to do java -jar app.jar I get this:
Exception in thread "JavaFX Application Thread" Exception in thread "main"
java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
at tao.qaflash.GUI.<clinit>(GUI.java:14)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplicationWithArgs$156(LauncherImpl.java:352)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 12 more
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.NullPointerException
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:383)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
... 5 more
My environment is: Java 1.8.0_92, Gradle 2.16, Eclipse Mars 4.5.0, Java FX.
Also I have googled this error and I have tried everything from there , but with no success. I tried to add to the build.gradle as dependencies slfj-simple, log4j, logback-classic, slf4j-jdk14,junit,vaadin-slf4j-jdk14 but the error kept appearing.
When I run the application from Eclipse, everything works fine, the logs are written, only when I try to run the jar from command line, I get this ClassNotFoundException.
build.gradle looks like :
dependencies {
compile 'net.sf.staf:jstaf:3.4.4'
// SLF4J API module which will be used for logging
compile 'org.slf4j:slf4j-api:1.7.21'
// Log4J2 logging framework including the binding module to slf4j
compile 'org.apache.logging.log4j:log4j-slf4j-impl:2.5'
compile 'org.apache.logging.log4j:log4j-api:2.5'
compile 'org.apache.logging.log4j:log4j-core:2.5'
testCompile 'junit:junit:4.12'
testCompile "org.testfx:testfx-core:4.0.+"
testCompile "org.testfx:testfx-junit:4.0.+"
}
Any help is greately appreciated.

Simple: the classpath that you are using when trying to execute your JAR file does not contain the required sl4j logger library.
That is all there is to this. This is not about your build setup - it is about the setup that gets used when you run java on the command line!
See here for further reading.

I have unzipped the zip file that was created in the dist folder and it works :) because in the lib folder there was the sl4j-api.

It seems you need slf4j at runtime as well. Have a look at the gradle dependency configuration options

After updating Intelij getting Exception in thread "main" java.lang.NoClassDefFoundError: org/testng/TestNG

After updating intelij i cannot run anymore testng.xml.
If i run my tests as a separate Class it works fine and runs. But if i run it as a suite Testng.xml i got error.
/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/bin/java -ea -Didea.launcher.port=7533 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA CE.app/Contents/bin" -Didea.testng.sm_runner -Dfile.encoding=UTF-8 -classpath "/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar:/Applications/IntelliJ IDEA CE.app/Contents/plugins/testng/lib/testng-plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home/lib/tools.jar:/Applications/IntelliJ IDEA CE.app/Contents/plugins/testng/lib/jcommander.jar" com.intellij.rt.execution.application.AppMain org.testng.RemoteTestNGStarter -port 63142 -usedefaultlisteners false -socket63143 #w#/private/var/folders/jq/g93n6rmj0xv6ccklv2l2xgs86xx4fm/T/idea_working_dirs_testng.tmp -temp /private/var/folders/jq/g93n6rmj0xv6ccklv2l2xgs86xx4fm/T/idea_testng.tmp
Exception in thread "main" java.lang.NoClassDefFoundError: org/testng/TestNG
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:117)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.ClassNotFoundException: org.testng.TestNG
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 18 more
Process finished with exit code 1
My Gradle configuration:
group 'ao-core-android'
version '1.0-SNAPSHOT'
apply plugin: 'java'
sourceCompatibility = 1.5
tasks.withType(Test) {
scanForTestClasses = false
include "**/*Test.class" // whatever Ant pattern matches your test class files
}
test {
useTestNG {
suites 'testng.xml'
}
}
repositories {
mavenCentral()
}
dependencies {
//testCompile group: 'junit', name: 'junit', version: '4.11'
compile 'org.testng:testng:6.9.10'
compile 'io.appium:java-client:4.0.0'
compile 'org.seleniumhq.selenium:selenium-java:2.53.1'
compile 'com.android.tools.build:gradle:1.1.0'
compile fileTree(dir: 'externalLibs', include: ['*.jar'])
compile files('./lib-test-tools-1.4.0.jar')
}
It highlights the
test {
useTestNG {
suites 'testng.xml'
}
}
in build.gradle.
And gives message :
test' cannot be applied to '(groovy.lang.Closure)' less... (⌘F1)
This inspection reports assignments with incompatible types

I had the same issue 'Anton Anton' reported when I ran a particular unit test. However, this didn't happen when I ran the entire suite with mvn clean test.
Exception in thread "main" java.lang.NoclassDefFoundError: org/test/TestNG
I came across this blog post in the IntelliJ Community which did work for me.
"I got it to work by selecting "In whole project" (I had "In single
module" selected) under the Configuration tab in the TestNG "Run/Debug
Configurations."
Credits to Serge Baranov and Leonardo Hernandez.