Error when running on Java 21-ea

[beikov]

Trying to run the 3.1.1 Maven plugin with Java 21-ea, I get the following error:

Error:  Failed to execute goal io.smallrye:jandex-maven-plugin:3.1.1:jandex (make-index) on project blaze-persistence-integration-graphql-spqr: A type incompatibility occurred while executing io.smallrye:jandex-maven-plugin:3.1.1:jandex: class java.lang.Object cannot be cast to class [B (java.lang.Object and [B are in module java.base of loader 'bootstrap')
Error:  -----------------------------------------------------
Error:  realm =    plugin>io.smallrye:jandex-maven-plugin:3.1.1
Error:  strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
Error:  urls[0] = file:/home/runner/.m2/repository/io/smallrye/jandex-maven-plugin/3.1.1/jandex-maven-plugin-3.1.1.jar
Error:  urls[1] = file:/home/runner/.m2/repository/org/codehaus/plexus/plexus-utils/3.5.0/plexus-utils-3.5.0.jar
Error:  urls[2] = file:/home/runner/.m2/repository/io/smallrye/jandex/3.1.1/jandex-3.1.1.jar
Error:  Number of foreign imports: 1
Error:  import: Entry[import  from realm ClassRealm[maven.api, parent: null]]

Any idea what the issue could be?

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f) Maven home: /home/runner/.m2/wrapper/dists/apache-maven-3.6.3-bin/1iopthnavndlasol9gbrbg6bf2/apache-maven-3.6.3 Java version: 21-ea, vendor: Azul Systems, Inc., runtime: /opt/hostedtoolcache/Java_Zulu_jdk/21.0.0-ea.22/x64 Default locale: en, platform encoding: UTF-8 OS name: "linux", version: "5.15.0-1037-azure", arch: "amd64", family: "unix"

[Ladicek]

I've downloaded https://search.maven.org/artifact/com.blazebit/blaze-persistence-integration-graphql-spqr/1.6.8/jar and trying to index it with these JDKs:

openjdk version "21-beta" 2023-09-19
OpenJDK Runtime Environment Temurin-21+22-202305251619 (build 21-beta+22-202305251619)
OpenJDK 64-Bit Server VM Temurin-21+22-202305251619 (build 21-beta+22-202305251619, mixed mode, sharing)

openjdk version "21-ea" 2023-09-19
OpenJDK Runtime Environment Zulu21+57-CA (build 21-ea+22)
OpenJDK 64-Bit Server VM Zulu21+57-CA (build 21-ea+22, mixed mode, sharing)

They both seem to work just fine (as in, they write an index file and don't fail).

Could you please provide a JAR on which indexing fails? Alternatively, a stack trace might be enough (mvn -X).

[beikov]

The problem appears when the module is compiled with the Java 21 class file version. I guess it doesn't really matter what the content of the JAR file is, as long as there is one class file compiled with the latest version.

[beikov]

So far, I reproduced this issue locally with Azul Zulu JDK 21-ea build 22. Here is the JAR (added .zip to the end because GitHub doesn't allow uploading JAR files): blaze-persistence-integration-graphql-spqr-1.6.9-SNAPSHOT.jar.zip

Here is the full error:

Caused by: org.apache.maven.plugin.PluginExecutionException: A type incompatibility occurred while executing io.smallrye:jandex-maven-plugin:3.1.1:jandex: class java.lang.Object cannot be cast to class [B (java.lang.Object and [B are in module java.base of loader 'bootstrap')
-----------------------------------------------------
realm =    plugin>io.smallrye:jandex-maven-plugin:3.1.1
strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
urls[0] = file:/C:/Users/cbeikov/.m2/repository/io/smallrye/jandex-maven-plugin/3.1.1/jandex-maven-plugin-3.1.1.jar
urls[1] = file:/C:/Users/cbeikov/.m2/repository/org/codehaus/plexus/plexus-utils/3.5.0/plexus-utils-3.5.0.jar
urls[2] = file:/C:/Users/cbeikov/.m2/repository/io/smallrye/jandex/3.1.1/jandex-3.1.1.jar
Number of foreign imports: 1
import: Entry[import  from realm ClassRealm[maven.api, parent: null]]

-----------------------------------------------------

    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:199)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:578)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:578)
    at org.apache.maven.wrapper.BootstrapMainStarter.start (BootstrapMainStarter.java:39)
    at org.apache.maven.wrapper.WrapperExecutor.execute (WrapperExecutor.java:122)
    at org.apache.maven.wrapper.MavenWrapperMain.main (MavenWrapperMain.java:61)
Caused by: java.lang.ClassCastException: class java.lang.Object cannot be cast to class [B (java.lang.Object and [B are in module java.base of loader 'bootstrap')
    at org.jboss.jandex.StrongInternPool$ByteArrayInternPool.hash (StrongInternPool.java:625)
    at org.jboss.jandex.StrongInternPool.intern (StrongInternPool.java:237)
    at org.jboss.jandex.NameTable.intern (NameTable.java:101)
    at org.jboss.jandex.IndexWriterV2.deepIntern (IndexWriterV2.java:1027)
    at org.jboss.jandex.IndexWriterV2.addMethodList (IndexWriterV2.java:1011)
    at org.jboss.jandex.IndexWriterV2.addClass (IndexWriterV2.java:932)
    at org.jboss.jandex.IndexWriterV2.buildTables (IndexWriterV2.java:888)
    at org.jboss.jandex.IndexWriterV2.write (IndexWriterV2.java:199)
    at org.jboss.jandex.IndexWriter.write (IndexWriter.java:102)
    at org.jboss.jandex.IndexWriter.write (IndexWriter.java:66)
    at org.jboss.jandex.maven.JandexGoal.execute (JandexGoal.java:172)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:578)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:578)
    at org.apache.maven.wrapper.BootstrapMainStarter.start (BootstrapMainStarter.java:39)
    at org.apache.maven.wrapper.WrapperExecutor.execute (WrapperExecutor.java:122)
    at org.apache.maven.wrapper.MavenWrapperMain.main (MavenWrapperMain.java:61)

[Ladicek]

No, that doesn't seem to reproduce. Do you have a Maven project I can clone and build myself? https://github.com/Blazebit/blaze-persistence doesn't seem to use Jandex 3.1.1 anywhere :thinking:

[beikov]

I do. Checkout the contents of this PR and first build with .\mvnw clean install -P "hibernate-5.6,h2,spring-data-2.7.x,deltaspike-1.9" "-Duser.country=US" "-Duser.language=en" "-Dmaven.javadoc.skip" "-Dmain.java.version=21" "-Dtest.java.version=21" "-Djdk8.home=<PATH_TO_JDK_8>" -DskipTests

It will fail at that module, but then you can build just that single module by appending -pl .\integration\graphql-spqr\

[beikov]

And don't forget to make sure that your JAVA_HOME env variable points to a JDK 21

[Ladicek]

OK, reproduced it now. Thanks!

[Ladicek]

OK, the issue is caused by the performance improvements made in Jandex 3.1.0. As part of those improvements, the hash table used for object interning was refactored to be more type-safe (with one subclass of the hash table per interned type), but the null marker object was left unchanged (a single new Object() instance). Replacing that global marker object with a per-subclass marker object solves the problem, but isn't exactly nice. I'll see if I can come up with something better.

[Ladicek]

I kept digging, because while my last comment is correct, there must be more to it, and indeed I found a really strange behavior of JDK 21.

Say I have these 2 classes:

public class Foo {
    public Foo(String... strings) {
    }
}

public class Bar {
    public Foo getFoo() {
        return new Foo() {};
    }
}

Then compiling them using javac -g *.java and then decompiling the inner class using javap -v -p Bar\$1.class leads to the following results:

JDK 8, 11, 17:

...

  Bar$1(Bar, java.lang.String...);
    descriptor: (LBar;[Ljava/lang/String;)V
    flags: ACC_VARARGS
    Code:
      stack=2, locals=3, args_size=3
         0: aload_0
         1: aload_1
         2: putfield      #1                  // Field this$0:LBar;
         5: aload_0
         6: aload_2
         7: invokespecial #2                  // Method Foo."<init>":([Ljava/lang/String;)V
        10: return
      LineNumberTable:
        line 3: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0      11     0  this   LBar$1;
            0      11     1 this$0   LBar;
            0      11     2 strings   [Ljava/lang/String;

...

JDK 21-ea:

...

  Bar$1(Bar, java.lang.String...);
    descriptor: (LBar;[Ljava/lang/String;)V
    flags: (0x0080) ACC_VARARGS
    Code:
      stack=2, locals=3, args_size=3
         0: aload_0
         1: aload_2
         2: invokespecial #1                  // Method Foo."<init>":([Ljava/lang/String;)V
         5: return
      LineNumberTable:
        line 3: 0
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
            0       6     0  this   LBar$1;
            0       6     1 this$0   LBar;
            0       6     2 strings   [Ljava/lang/String;
    MethodParameters:
      Name                           Flags
      <no name>                      final mandated
      <no name>

...

That is, javac from JDK 21-ea produces the MethodParameters attribute even if -parameters was not used. The attribute has a name_index of 0 for each parameter, which is valid per the JVMS, but Jandex can't cope with it. So that needs fixing too.

[Ladicek]

Aside: if -parameters is passed to javac, then the MethodParameters attribute is as-expected on all tested JDKs:

    MethodParameters:
      Name                           Flags
      this$0                         final mandated
      strings

[Ladicek]

For historical reference, here are JDK issues that explain the differences in bytecode demonstrated above:

• https://bugs.openjdk.org/browse/JDK-8271623
• https://bugs.openjdk.org/browse/JDK-8292275