Java 注释处理期间GWT RfValidator NPE

在aspectjrt大于1.8.5版的情况下使用aspectjweaver 1.11版会导致在使用Java 8构建GWT 1.8.2应用程序的过程中出现多个NPE：

[INFO] --- aspectj-maven-plugin:1.11:compile (compile) @ myproject ---
...
[ERROR] java.lang.NullPointerException
    at org.aspectj.org.eclipse.jdt.internal.compiler.lookup.FieldBinding.sourceField(FieldBinding.java:437)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.model.TypeElementImpl$SourceLocationComparator.determineSourceStart(TypeElementImpl.java:110)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.model.TypeElementImpl$SourceLocationComparator.getSourceStart(TypeElementImpl.java:74)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.model.TypeElementImpl$SourceLocationComparator.compare(TypeElementImpl.java:67)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.model.TypeElementImpl$SourceLocationComparator.compare(TypeElementImpl.java:1)
    at java.util.TimSort.countRunAndMakeAscending(TimSort.java:360)
    at java.util.TimSort.sort(TimSort.java:234)
    at java.util.Arrays.sort(Arrays.java:1512)
    at java.util.ArrayList.sort(ArrayList.java:1462)
    at java.util.Collections.sort(Collections.java:175)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.model.TypeElementImpl.getEnclosedElements(TypeElementImpl.java:168)
    at com.google.web.bindery.requestfactory.apt.DomainChecker.isDefaultInstantiable(DomainChecker.java:407)
    at com.google.web.bindery.requestfactory.apt.DomainChecker.visitType(DomainChecker.java:253)
    at com.google.web.bindery.requestfactory.apt.DomainChecker.visitType(DomainChecker.java:44)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.model.TypeElementImpl.accept(TypeElementImpl.java:139)
    at javax.lang.model.util.ElementScanner6.scan(ElementScanner6.java:146)
    at com.google.web.bindery.requestfactory.apt.ScannerBase.scan(ScannerBase.java:76)
    at com.google.web.bindery.requestfactory.apt.State.executeJobs(State.java:248)
    at com.google.web.bindery.requestfactory.apt.RfValidator.process(RfValidator.java:86)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.handleProcessor(RoundDispatcher.java:142)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.round(RoundDispatcher.java:124)
    at org.aspectj.org.eclipse.jdt.internal.compiler.apt.dispatch.BaseAnnotationProcessorManager.processAnnotations(BaseAnnotationProcessorManager.java:171)
    at org.aspectj.org.eclipse.jdt.internal.compiler.Compiler.processAnnotations(Compiler.java:956)
    at org.aspectj.org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:451)
    at org.aspectj.org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:427)
    at org.aspectj.ajdt.internal.core.builder.AjBuildManager.performCompilation(AjBuildManager.java:1107)
    at org.aspectj.ajdt.internal.core.builder.AjBuildManager.performBuild(AjBuildManager.java:276)
    at org.aspectj.ajdt.internal.core.builder.AjBuildManager.batchBuild(AjBuildManager.java:189)
    at org.aspectj.ajdt.ajc.AjdtCommand.doCommand(AjdtCommand.java:114)
    at org.aspectj.ajdt.ajc.AjdtCommand.runCommand(AjdtCommand.java:60)
    at org.aspectj.tools.ajc.Main.run(Main.java:371)
    at org.aspectj.tools.ajc.Main.runMain(Main.java:248)
    at org.codehaus.mojo.aspectj.AbstractAjcCompiler.execute(AbstractAjcCompiler.java:544)
    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:956)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:192)
    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)

这发生在所有@ProxyFor类中，这些类是项目外部类的代理（由maven依赖项解决）

@ProxyFor（value=ClassOfOtherProject.class）
其他ProjectProxy的公共接口类扩展了EntityProxy{/这在GWT编译中并没有失败，只是在将java源代码编译为字节码的过程中失败了。GWT的RequestFactory使用注释处理器来验证您的每个代理是否正确匹配它们在服务器上映射到的实体/值/服务类型，并且该版本的aspectjrt和jdt似乎可以通过某种方式无法正确查找其他项目的
类的成员，以便对其进行筛选以找到构造函数。请从堆栈跟踪中，在
com/google/web/bindery/requestfactory/apt/DomainChecker.java:407
：

List<ExecutableElement> constructors = ElementFilter.constructorsIn(x.getEnclosedElements());

List constructors=ElementFilter.constructorsIn（x.getEnclosedElements（））；

这是在注释处理器中执行操作的一种非常标准的方法-如果调用TypeElement.getEnclosedElements（）如果此注释处理器的NPE失败，我也会担心此版本中的其他错误。这很可能发生在任何注释处理器上，与GWT无关。
我最终能够使用最新的AspectJ运行时构建我的项目，方法是让maven编译器插件只执行anno操作正在处理。只需将
仅添加到插件的配置中即可

类编译将由aspectj maven插件完成。可以通过向配置中添加
none
来禁用此插件的注释处理

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.1</version>
    <configuration>
        <source>1.8</source>
        <target>1.8</target>
        <useIncrementalCompilation>false</useIncrementalCompilation>
        <encoding>UTF-8</encoding>
        <annotationProcessors>
            <annotationProcessor>com.google.web.bindery.requestfactory.apt.RfValidator</annotationProcessor>
        </annotationProcessors>
    </configuration>
    <dependencies>
        <dependency>
            <groupId>com.google.web.bindery</groupId>
            <artifactId>requestfactory-apt</artifactId>
            <version>2.8.2</version>
        </dependency>
    </dependencies>
</plugin>

List<ExecutableElement> constructors = ElementFilter.constructorsIn(x.getEnclosedElements());