The VM calls System::initPhase2 to initialization the module system as part of create the VM. If initPhase2 fails (with an exception) then the VM aborts after printing the stack trace.

This issue tracks changing this so that the exception (and optional cause) are printed by default without the stack trace. For diagnosability reasons then having way to print the stack trace will be needed.

As a simple example, consider the following:

$ java -p mods --add-modules x,y -version
Error occurred during initialization of VM
java.lang.RuntimeException: Package p in both module y and module x
at jdk.internal.module.ModuleBootstrap.fail(java.base@9-internal/ModuleBootstrap.java:705)
at jdk.internal.module.ModuleBootstrap.boot(java.base@9-internal/ModuleBootstrap.java:335)
at java.lang.System.initPhase2(java.base@9-internal/System.java:1928)

Another example, where the exception cause is very useful but is hard to see with the large stack trace.

$ java -p mods -version
Error occurred during initialization of VM
java.lang.module.FindException: Error reading module: mods/x
at jdk.internal.module.ModulePath.readModule(java.base@9-internal/ModulePath.java:333)
at jdk.internal.module.ModulePath.scanDirectory(java.base@9-internal/ModulePath.java:284)
at jdk.internal.module.ModulePath.scan(java.base@9-internal/ModulePath.java:232)
at jdk.internal.module.ModulePath.scanNextEntry(java.base@9-internal/ModulePath.java:190)
at jdk.internal.module.ModulePath.findAll(java.base@9-internal/ModulePath.java:166)
at java.lang.module.ModuleFinder$2.lambda$findAll$2(java.base@9-internal/ModuleFinder.java:382)
at java.util.stream.ReferencePipeline$7$1.accept(java.base@9-internal/ReferencePipeline.java:269)
at java.util.AbstractList$RandomAccessSpliterator.forEachRemaining(java.base@9-internal/AbstractList.java:720)
at java.util.stream.AbstractPipeline.copyInto(java.base@9-internal/AbstractPipeline.java:484)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(java.base@9-internal/AbstractPipeline.java:474)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(java.base@9-internal/ForEachOps.java:151)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(java.base@9-internal/ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(java.base@9-internal/AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(java.base@9-internal/ReferencePipeline.java:430)
at java.lang.module.ModuleFinder$2.findAll(java.base@9-internal/ModuleFinder.java:383)
at java.lang.module.Resolver.findAll(java.base@9-internal/Resolver.java:872)
at java.lang.module.Resolver.bind(java.base@9-internal/Resolver.java:240)
at java.lang.module.Configuration.resolveAndBind(java.base@9-internal/Configuration.java:257)
at java.lang.module.ModuleDescriptor$1.resolveAndBind(java.base@9-internal/ModuleDescriptor.java:2792)
at jdk.internal.module.ModuleBootstrap.boot(java.base@9-internal/ModuleBootstrap.java:284)
at java.lang.System.initPhase2(java.base@9-internal/System.java:1928)
Caused by: java.lang.module.InvalidModuleDescriptorException: Truncated module-info.class
at jdk.internal.module.ModuleInfo.invalidModuleDescriptor(java.base@9-internal/ModuleInfo.java:1069)
at jdk.internal.module.ModuleInfo.truncatedModuleDescriptor(java.base@9-internal/ModuleInfo.java:1077)
at jdk.internal.module.ModuleInfo.read(java.base@9-internal/ModuleInfo.java:127)
at jdk.internal.module.ModulePath.readExplodedModule(java.base@9-internal/ModulePath.java:655)
at jdk.internal.module.ModulePath.readModule(java.base@9-internal/ModulePath.java:319)
at jdk.internal.module.ModulePath.scanDirectory(java.base@9-internal/ModulePath.java:284)
at jdk.internal.module.ModulePath.scan(java.base@9-internal/ModulePath.java:232)
at jdk.internal.module.ModulePath.scanNextEntry(java.base@9-internal/ModulePath.java:190)
at jdk.internal.module.ModulePath.findAll(java.base@9-internal/ModulePath.java:166)
at java.lang.module.ModuleFinder$2.lambda$findAll$2(java.base@9-internal/ModuleFinder.java:382)
at java.util.stream.ReferencePipeline$7$1.accept(java.base@9-internal/ReferencePipeline.java:269)
at java.util.AbstractList$RandomAccessSpliterator.forEachRemaining(java.base@9-internal/AbstractList.java:720)
at java.util.stream.AbstractPipeline.copyInto(java.base@9-internal/AbstractPipeline.java:484)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(java.base@9-internal/AbstractPipeline.java:474)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(java.base@9-internal/ForEachOps.java:151)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(java.base@9-internal/ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(java.base@9-internal/AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(java.base@9-internal/ReferencePipeline.java:430)
at java.lang.module.ModuleFinder$2.findAll(java.base@9-internal/ModuleFinder.java:383)
at java.lang.module.Resolver.findAll(java.base@9-internal/Resolver.java:872)
at java.lang.module.Resolver.bind(java.base@9-internal/Resolver.java:240)
at java.lang.module.Configuration.resolveAndBind(java.base@9-internal/Configuration.java:257)
at java.lang.module.ModuleDescriptor$1.resolveAndBind(java.base@9-internal/ModuleDescriptor.java:2792)
at jdk.internal.module.ModuleBootstrap.boot(java.base@9-internal/ModuleBootstrap.java:284)
at java.lang.System.initPhase2(java.base@9-internal/System.java:1928)