Does not build or run with java9

[git4skatz]

Tried with Java9.0.4

Build time error:
[INFO] Running org.cyclopsgroup.jmxterm.pm.JConsoleClassLoaderFactoryTest
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.049 s <<< FAILURE! - in org.cyclopsgroup.jmxterm.pm.JConsoleClassLoaderFactoryTest
[ERROR] testLoad(org.cyclopsgroup.jmxterm.pm.JConsoleClassLoaderFactoryTest) Time elapsed: 0.012 s <<< ERROR!
java.lang.RuntimeException: Operation requires JDK instead of JRE
at org.cyclopsgroup.jmxterm.pm.JConsoleClassLoaderFactoryTest.testLoad(JConsoleClassLoaderFactoryTest.java:22)

Runtime error:
:~/Downloads$ java -jar jmxterm-1.0.0-uber.jar
java.lang.NullPointerException
at org.codehaus.classworlds.Launcher.getEnhancedMainMethod(Launcher.java:195)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:294)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.codehaus.classworlds.uberjar.boot.Bootstrapper.bootstrap(Bootstrapper.java:209)
at org.codehaus.classworlds.uberjar.boot.Bootstrapper.main(Bootstrapper.java:116)

[hyproman]

Same behavior on 10.0.1:

java version "10.0.1" 2018-04-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.1+10)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.1+10, mixed mode)

[jfharden]

And in 12, and 14ea:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.20.1:test (default-test) on project jmxterm: Execution default-test of goal org.apache.maven.plugins:maven-surefire-plugin:2.20.1:test failed.: NullPointerException -> [Help 1]

...

bash-4.2# java -version
openjdk version "12.0.2" 2019-07-16
OpenJDK Runtime Environment (build 12.0.2+10)
OpenJDK 64-Bit Server VM (build 12.0.2+10, mixed mode, sharing)

bash-4.2# java -version
openjdk version "14-ea" 2020-03-17
OpenJDK Runtime Environment (build 14-ea+14-570)
OpenJDK 64-Bit Server VM (build 14-ea+14-570, mixed mode, sharing)

[SandroGrzicic]

After making a local build with upgraded dependencies, setting "source" and "target" of maven-compiler-plugin in the POM to "13", building on AdoptOpenJDK 13 works fine, and running it under the same JDK 13 works and the console can be used, however when trying to "open" (connect to) a process I get the following Unable to detect the run-time image error which I cannot resolve:

Listing available beans...
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.cyclopsgroup.jmxterm.utils.WeakCastUtils$2 (file:jmxterm-1.0.1-uber.jar) to method sun.tools.jconsole.LocalVirtualMachine.getAllVirtualMachines()
WARNING: Please consider reporting this to the maintainers of org.cyclopsgroup.jmxterm.utils.WeakCastUtils$2
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Exception in thread "main" java.lang.reflect.UndeclaredThrowableException
	at com.sun.proxy.$Proxy7.startManagementAgent(Unknown Source)
	at org.cyclopsgroup.jmxterm.jdk6.Jdk6JavaProcess.startManagementAgent(Jdk6JavaProcess.java:39)
	at org.cyclopsgroup.jmxterm.SyntaxUtils.getUrl(SyntaxUtils.java:51)
	at org.cyclopsgroup.jmxterm.boot.CliMain.execute(CliMain.java:127)
	at org.cyclopsgroup.jmxterm.boot.CliMain.main(CliMain.java:41)
Caused by: com.sun.tools.attach.AttachOperationFailedException: java.lang.InternalError: Unable to detect the run-time image
	at jdk.attach/sun.tools.attach.VirtualMachineImpl.execute(VirtualMachineImpl.java:224)
	at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:309)
	at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.executeJCmd(HotSpotVirtualMachine.java:291)
	at jdk.attach/sun.tools.attach.HotSpotVirtualMachine.startLocalManagementAgent(HotSpotVirtualMachine.java:250)
	at jdk.jconsole/sun.tools.jconsole.LocalVirtualMachine.loadManagementAgent(LocalVirtualMachine.java:237)
	at jdk.jconsole/sun.tools.jconsole.LocalVirtualMachine.startManagementAgent(LocalVirtualMachine.java:96)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
	at org.cyclopsgroup.jmxterm.utils.WeakCastUtils$1.invoke(WeakCastUtils.java:53)
	... 5 more

The error appears to come from here:

https://github.com/AdoptOpenJDK/openjdk-jdk/blob/master/src/java.base/share/classes/jdk/internal/module/SystemModuleFinders.java#L210

However, executing java.lang.module.ModuleFinder.ofSystem() (which calls SystemModuleFinders.ofSystem) in a separate Java program on the same JDK works fine.

Version:

openjdk version "13" 2019-09-17
OpenJDK Runtime Environment AdoptOpenJDK (build 13+33)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 13+33, mixed mode, sharing)

[nyg]

If you want a quick fix, you can check this StackOverflow question and answers: https://stackoverflow.com/q/75239006.

However, using --add-exports means dropping support for Java 8 (unless jmxterm defines multiple build profiles) and more importantly can't be used with the new release option of javac (the jdk.jconsole module is not part of the public API).