Trouble running unetstack community edition 3.4.4 on Ubuntu 24.04 (LTS)

[newr5]

Hi,
I am running Ubuntu 24.04 (LTS) and have downloaded the community edition of UnetStack.
When attempting to run 'bin/unet samples/2-node-network.groovy' (as in the handbook), I get the following error messages:

java.lang.NoClassDefFoundError: Could not initialize class org.codehaus.groovy.vmplugin.v7.Java7
        at org.codehaus.groovy.vmplugin.VMPluginFactory.<clinit>(VMPluginFactory.java:43)
        at org.codehaus.groovy.reflection.GroovyClassValueFactory.<clinit>(GroovyClassValueFactory.java:35)
        at org.codehaus.groovy.reflection.ClassInfo.<clinit>(ClassInfo.java:107)
        at org.codehaus.groovy.reflection.ReflectionCache.getCachedClass(ReflectionCache.java:95)
        at org.codehaus.groovy.reflection.ReflectionCache.<clinit>(ReflectionCache.java:39)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.registerMethods(MetaClassRegistryImpl.java:210)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:108)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:86)
        at groovy.lang.GroovySystem.<clinit>(GroovySystem.java:36)
        at org.codehaus.groovy.runtime.InvokerHelper.<clinit>(InvokerHelper.java:86)
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Class.java:534)
        at java.base/java.lang.Class.forName(Class.java:513)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray$1.run(CallSiteArray.java:67)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray$1.run(CallSiteArray.java:64)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:319)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallStaticSite(CallSiteArray.java:64)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallSite(CallSiteArray.java:161)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:115)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:135)
        at org.arl.unet.UnetBoot.main(UnetBoot.groovy)
Caused by: java.lang.ExceptionInInitializerError: Exception org.codehaus.groovy.GroovyBugError [in thread "main"]
        at org.codehaus.groovy.vmplugin.v7.Java7.<clinit>(Java7.java:45)
        at java.base/jdk.internal.misc.Unsafe.ensureClassInitialized0(Native Method)
        at java.base/jdk.internal.misc.Unsafe.ensureClassInitialized(Unsafe.java:1160)
        at java.base/jdk.internal.reflect.MethodHandleAccessorFactory.ensureClassInitialized(MethodHandleAccessorFactory.java:300)
        at java.base/jdk.internal.reflect.MethodHandleAccessorFactory.newConstructorAccessor(MethodHandleAccessorFactory.java:103)
        at java.base/jdk.internal.reflect.ReflectionFactory.newConstructorAccessor(ReflectionFactory.java:200)
        at java.base/java.lang.reflect.Constructor.acquireConstructorAccessor(Constructor.java:549)
        at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:486)
        at org.codehaus.groovy.vmplugin.VMPluginFactory.createPlugin(VMPluginFactory.java:57)
        at org.codehaus.groovy.vmplugin.VMPluginFactory.<clinit>(VMPluginFactory.java:39)
        ... 21 more
Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class org.codehaus.groovy.reflection.ReflectionCache
        at org.codehaus.groovy.runtime.dgmimpl.NumberNumberMetaMethod.<clinit>(NumberNumberMetaMethod.java:33)
        at java.base/jdk.internal.misc.Unsafe.ensureClassInitialized0(Native Method)
        at java.base/jdk.internal.misc.Unsafe.ensureClassInitialized(Unsafe.java:1160)
        at java.base/jdk.internal.reflect.MethodHandleAccessorFactory.ensureClassInitialized(MethodHandleAccessorFactory.java:300)
        at java.base/jdk.internal.reflect.MethodHandleAccessorFactory.newConstructorAccessor(MethodHandleAccessorFactory.java:103)
        at java.base/jdk.internal.reflect.ReflectionFactory.newConstructorAccessor(ReflectionFactory.java:200)
        at java.base/java.lang.reflect.Constructor.acquireConstructorAccessor(Constructor.java:549)
        at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:486)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.createMetaMethodFromClass(MetaClassRegistryImpl.java:258)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:111)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:86)
        at groovy.lang.GroovySystem.<clinit>(GroovySystem.java:36)
        at org.codehaus.groovy.runtime.InvokerHelper.<clinit>(InvokerHelper.java:86)
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Class.java:534)
        at java.base/java.lang.Class.forName(Class.java:513)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray$1.run(CallSiteArray.java:67)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray$1.run(CallSiteArray.java:64)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:319)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallStaticSite(CallSiteArray.java:64)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallSite(CallSiteArray.java:161)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:115)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:135)
        at org.arl.unet.UnetBoot.main(UnetBoot.groovy)
Caused by: java.lang.ExceptionInInitializerError: Exception java.lang.NoClassDefFoundError: Could not initialize class org.codehaus.groovy.vmplugin.v7.Java7 [in thread "main"]
        at org.codehaus.groovy.vmplugin.VMPluginFactory.<clinit>(VMPluginFactory.java:43)
        at org.codehaus.groovy.reflection.GroovyClassValueFactory.<clinit>(GroovyClassValueFactory.java:35)
        at org.codehaus.groovy.reflection.ClassInfo.<clinit>(ClassInfo.java:107)
        at org.codehaus.groovy.reflection.ReflectionCache.getCachedClass(ReflectionCache.java:95)
        at org.codehaus.groovy.reflection.ReflectionCache.<clinit>(ReflectionCache.java:39)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.registerMethods(MetaClassRegistryImpl.java:210)
        at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:108)
        ... 15 more

I have installed both the default-jre and the default-jdk Ubuntu packages, which are aliased to openjdk-21.

Any idea how I can run the UnetStack software on my computer?

Thank you very much in advance.

[mchitre]

UnetStack needs JDK8, and does not work with JDK21. Please install JDK8 and try again.