NullPointerException: Cannot invoke "java.net.URL.getFile()" because the return value of "org.hotswap.agent.javassist.ClassPool.find(String)" is null

[reubenfirmin]

This is a Kotlin project, using gradle to run the application with OpenJDK 17. Works for some time and then errors with the following. (My gradle config is in: #521)

HOTSWAP AGENT: 10:23:15.915 ERROR (org.hotswap.agent.annotation.handler.PluginClassFileTransformer) - InvocationTargetException in transform method on plugin 'class org.hotswap.agent.plugin.jvm.AnonymousClassPatchPlugin' class 'ah/view/pages/DashboardPage$Companion$acquisitionOverview$1$4$1$1$1$1'.
java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:568)
        at org.hotswap.agent.annotation.handler.PluginClassFileTransformer.transform(PluginClassFileTransformer.java:218)
        at org.hotswap.agent.annotation.handler.PluginClassFileTransformer.transform(PluginClassFileTransformer.java:112)
        at org.hotswap.agent.util.HotswapTransformer.transform(HotswapTransformer.java:246)
        at java.instrument/java.lang.instrument.ClassFileTransformer.transform(ClassFileTransformer.java:244)
        at java.instrument/sun.instrument.TransformerManager.transform(TransformerManager.java:188)
        at java.instrument/sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:541)
        at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses0(Native Method)
        at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses(InstrumentationImpl.java:195)
        at org.hotswap.agent.config.PluginManager.hotswap(PluginManager.java:292)
        at org.hotswap.agent.plugin.hotswapper.HotswapperPlugin$1.executeCommand(HotswapperPlugin.java:112)
        at org.hotswap.agent.command.impl.CommandExecutor.run(CommandExecutor.java:43)
Caused by: java.lang.NullPointerException: Cannot invoke "java.net.URL.getFile()" because the return value of "org.hotswap.agent.javassist.ClassPool.find(String)" is null
        at org.hotswap.agent.plugin.jvm.AnonymousClassInfos.lastModified(AnonymousClassInfos.java:270)
        at org.hotswap.agent.plugin.jvm.AnonymousClassInfos.<init>(AnonymousClassInfos.java:108)
        at org.hotswap.agent.plugin.jvm.AnonymousClassPatchPlugin.getStateInfo(AnonymousClassPatchPlugin.java:244)
        at org.hotswap.agent.plugin.jvm.AnonymousClassPatchPlugin.patchAnonymousClass(AnonymousClassPatchPlugin.java:104)
        ... 15 more
Exception in thread "Thread-265" java.lang.IllegalStateException: Unable to redefine classes

        at org.hotswap.agent.config.PluginManager.hotswap(PluginManager.java:296)
        at org.hotswap.agent.plugin.hotswapper.HotswapperPlugin$1.executeCommand(HotswapperPlugin.java:112)
        at org.hotswap.agent.command.impl.CommandExecutor.run(CommandExecutor.java:43)
Caused by: java.lang.UnsupportedOperationException: class redefinition failed: attempted to add a method
        at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses0(Native Method)
        at java.instrument/sun.instrument.InstrumentationImpl.redefineClasses(InstrumentationImpl.java:195)
        at org.hotswap.agent.config.PluginManager.hotswap(PluginManager.java:292)
        ... 2 more

[skybber]

Standard redefinition in OpenJDK does not support method addition, advanced redefinition -XX:+AllowEnhancedClassRedefinition is supported by jbr17.

[reubenfirmin]

Is there no way to make it work with OpenJDK? Having project contributers all use the JBR may be challenging.

[skybber]

Dcevm is not implemented in OpenJDK, so no way with OpenJDK. I can recommend you JBR builds on GitHub, there are many JBR build variants.