java Intellij Idea：使用IBM JDK 7构建项目的问题

Question

我有一个需要与IBM JDK 7一起使用的项目。我在windows 7上使用Intellij Idea 15.0.2。我的项目是多模块maven项目，使用了一些groovy脚本，还使用gradle使用maven org.fortasoft:gradle-maven-plugin将POM展平。现在，当我尝试构建我的应用程序（Build -> Rebuild Project）时，我在Messages窗口中遇到了一个单行错误

Error:java.lang.NullPointerException

当我检查构建时。日志（C:\Users\.IntelliJIdea15\system\log\build log\build.log），我看到以下异常。只要我将project SDK更改为Oracle JDK 7，一切都正常。知道这里出了什么问题吗

[Update 1:]我还试图使缓存无效，并重新启动了这个想法，只是为了排除缓存在这里的恶意行为

2015-12-22 14:16:23,343 [   4126]   INFO - .incremental.IncProjectBuilder - java.lang.NullPointerException
org.jetbrains.jps.incremental.ProjectBuildException: java.lang.NullPointerException
     at org.jetbrains.jps.incremental.groovy.GroovyBuilder.build(GroovyBuilder.java:142)
     at org.jetbrains.jps.incremental.IncProjectBuilder.runModuleLevelBuilders(IncProjectBuilder.java:1230)
     at org.jetbrains.jps.incremental.IncProjectBuilder.runBuildersForChunk(IncProjectBuilder.java:904)
     at org.jetbrains.jps.incremental.IncProjectBuilder.buildTargetsChunk(IncProjectBuilder.java:976)
     at org.jetbrains.jps.incremental.IncProjectBuilder.buildChunkIfAffected(IncProjectBuilder.java:870)
     at org.jetbrains.jps.incremental.IncProjectBuilder.buildChunks(IncProjectBuilder.java:695)
     at org.jetbrains.jps.incremental.IncProjectBuilder.runBuild(IncProjectBuilder.java:386)
     at org.jetbrains.jps.incremental.IncProjectBuilder.build(IncProjectBuilder.java:193)
     at org.jetbrains.jps.cmdline.BuildRunner.runBuild(BuildRunner.java:137)
     at org.jetbrains.jps.cmdline.BuildSession.runBuild(BuildSession.java:294)
     at org.jetbrains.jps.cmdline.BuildSession.run(BuildSession.java:125)
     at org.jetbrains.jps.cmdline.BuildMain$MyMessageHandler$1.run(BuildMain.java:232)
     at org.jetbrains.jps.service.impl.SharedThreadPoolImpl$1.run(SharedThreadPoolImpl.java:42)
     at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:482)
     at java.util.concurrent.FutureTask.run(FutureTask.java:273)
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1176)
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
     at java.lang.Thread.run(Thread.java:795)
Caused by: java.lang.NullPointerException
     at java.lang.ClassLoader.loadClass(ClassLoader.java:731)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:707)
     at org.jetbrains.jps.incremental.groovy.InProcessGroovyc.createCompilationClassLoader(InProcessGroovyc.java:179)
     at org.jetbrains.jps.incremental.groovy.InProcessGroovyc.runGroovyc(InProcessGroovyc.java:76)
     at org.jetbrains.jps.incremental.groovy.GroovyBuilder.runGroovycOrContinuation(GroovyBuilder.java:201)
     at org.jetbrains.jps.incremental.groovy.GroovyBuilder.build(GroovyBuilder.java:117)
     ... 17 more

Answer 1

Any idea on whats going wrong here?

如果我们查看InProcessGroovyc.createCompilationClassLoader，我们可以看到代码

 private JointCompilationClassLoader createCompilationClassLoader(Collection<String> compilationClassPath) throws Exception {
    ClassLoader parent = obtainParentLoader(compilationClassPath);

    ClassLoader groovyClassLoader = null;
    try {
      ClassLoader auxiliary = parent != null ? parent : buildCompilationClassLoader(compilationClassPath, null).get();
      Class<?> gcl = auxiliary.loadClass("groovy.lang.GroovyClassLoader"); // 179 line, we throw NullPointer Exception

在类加载器中。负荷等级

public Class<?> loadClass(String name) throws ClassNotFoundException {
    return loadClass(name, false); // 131 line
}


protected Class<?> loadClass(String name, boolean resolve)
        throws ClassNotFoundException
    {
        synchronized (getClassLoadingLock(name)) {
            // First, check if the class has already been loaded
            Class<?> c = findLoadedClass(name); // return null if class not found 

所以IBM JDK 7找不到groovy.lang.GroovyClassLoader的主要问题是，请检查groovy安装是否正确，IBM JDK可以看到groovy库（groovy已下载，GROOVY_HOME环境变量设置正确，GROOVY_HOME/bin已添加到PATH环境变量）

Answer 2

看来这实际上是v15的一个bug。0.2. 解决方法是在Settings | Build, Execution, Deployment | Compiler | User-local build process VM options下添加-Didea.parallel.class.loader=false

更多细节here。v15应该提供修复程序。0.3. 直到那时，这种变通方法才奏效（至少对我来说是这样）