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NPE in ClassDumper

See original GitHub issue

After adding the the linkage-checker-enforcer-rules 1.2.0 to my pom, with:

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-enforcer-plugin</artifactId>
                <version>3.0.0-M3</version>
                <dependencies>
                    <dependency>
                        <groupId>com.google.cloud.tools</groupId>
                        <artifactId>linkage-checker-enforcer-rules</artifactId>
                        <version>1.2.0</version>
                    </dependency>
                </dependencies>
                <executions>
                    <execution>
                        <id>enforce-linkage-checker</id>
                        <phase>verify</phase>
                        <goals>
                            <goal>enforce</goal>
                        </goals>
                        <configuration>
                            <rules>
                                <LinkageCheckerRule implementation= "com.google.cloud.tools.dependencies.enforcer.LinkageCheckerRule">
                                    <level>WARN</level>
                                </LinkageCheckerRule>
                            </rules>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

I encountered the following exception, immediately after the enforcer plugin gave the following warnings

[WARNING] The POM for xerces:xerces-impl:jar:2.6.2 is missing, no dependency information available
[WARNING] The POM for net.sf.ehcache:sizeof-agent:jar:1.0.1 is missing, no dependency information available
[WARNING] The POM for com.ibm.websphere:websphere_uow_api:jar:0.0.1 is missing, no dependency information available
[WARNING] The POM for com.ibm.websphere:uow:jar:6.0.2.17 is missing, no dependency information available
[WARNING] net.sf.ehcache:sizeof-agent:jar:1.0.1 was not resolved. Dependency path: com.xyz:internal-util:jar:1-SNAPSHOT > com.xyz:internal-shaded:jar:1.234 (compile) > net.sf.ehcache:ehcache-core:jar:2.6.11 (compile) > net.sf.ehcache:sizeof-agent:jar:1.0.1 (provided)

Execution enforce-linkage-checker of goal org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M3:enforce failed.
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:215)
    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 sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    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)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution enforce-linkage-checker of goal org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M3:enforce failed.
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:148)
    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 sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    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)
Caused by: java.lang.NullPointerException
    at org.apache.bcel.generic.MethodGen.<init> (MethodGen.java:182)
    at com.google.cloud.tools.opensource.classpath.ClassDumper.catchesLinkageError (ClassDumper.java:500)
    at com.google.cloud.tools.opensource.classpath.ClassDumper.catchesLinkageError (ClassDumper.java:518)
    at com.google.cloud.tools.opensource.classpath.LinkageChecker.findSymbolProblem (LinkageChecker.java:482)
    at com.google.cloud.tools.opensource.classpath.LinkageChecker.lambda$findSymbolProblems$1 (LinkageChecker.java:180)
    at com.google.common.collect.ImmutableMultimap.lambda$null$2 (ImmutableMultimap.java:606)
    at java.lang.Iterable.forEach (Iterable.java:75)
    at com.google.common.collect.ImmutableMultimap.lambda$forEach$3 (ImmutableMultimap.java:606)
    at com.google.common.collect.RegularImmutableMap.forEach (RegularImmutableMap.java:185)
    at com.google.common.collect.ImmutableMultimap.forEach (ImmutableMultimap.java:605)
    at com.google.cloud.tools.opensource.classpath.LinkageChecker.findSymbolProblems (LinkageChecker.java:150)
    at com.google.cloud.tools.dependencies.enforcer.LinkageCheckerRule.execute (LinkageCheckerRule.java:203)
    at org.apache.maven.plugins.enforcer.EnforceMojo.execute (EnforceMojo.java:205)
    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 sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:498)
    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)

Issue Analytics

  • State:closed
  • Created 3 years ago
  • Comments:10 (5 by maintainers)

github_iconTop GitHub Comments

1reaction
suztomocommented, Apr 14, 2020

Thank you for the pom.xml. I’m able to reproduce the error. Continuing investigation.

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M3:enforce (enforce-linkage-checker) on project linkage-checker-error: Execution enforce-linkage-checker of goal org.apache.maven.plugins:maven-enforcer-plugin:3.0.0-M3:enforce failed.: NullPointerException -> [Help 1]

Memo:

javax.mail.internet.MailDateFormat is in javax:javaee-api:6.0:

Screen Shot 2020-04-14 at 10 22 13

BCEL’s MethodGen’s constructor has m.getCode().getCode(). The first m.getCode() is returning null for MailDateFormat’s constructor.

    public MethodGen(final Method m, final String class_name, final ConstantPoolGen cp) {
        this(m.getAccessFlags(), Type.getReturnType(m.getSignature()), Type.getArgumentTypes(m
                .getSignature()), null /* may be overridden anyway */
        , m.getName(), class_name,
                ((m.getAccessFlags() & (Const.ACC_ABSTRACT | Const.ACC_NATIVE)) == 0)
                        ? new InstructionList(m.getCode().getCode())
                        : null, cp);

I created a test d2975fc1c9b2598cad0fe963ea89178a7a7f5bb6 that fails due to this.

Investigating whether this is a bug in BCEL or expected NullPointerException the constructor.

There’s no byte code associated to the constructor https://gist.github.com/suztomo/97c3054b4bb320fefaaeafae4f6581af :

  public javax.mail.internet.MailDateFormat();
    descriptor: ()V
    flags: ACC_PUBLIC

Instantiating javax.mail.internet.MailDateFormat fails at runtime. Therefore BCEL’s expectation for the constructor to have the code is valid.

Screen Shot 2020-04-14 at 10 43 31

Question for BCEL is whether it’s more appropriate to throw more descriptive Exception upon such invalid class files.

Created a ticket for BCEL: BCEL-336.

0reactions
suztomocommented, Apr 15, 2020

I released com.google.cloud.tools:linkage-checker-enforcer-rules:1.2.1

Read more comments on GitHub >

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