NullAway初始化断言错误排查：无法检测Java空指针异常

错误栈 #

java.lang.AssertionError: com.google.errorprone.scanner.ErrorProneInjector$ProvisionException: Failed to initialize com.uber.nullaway.NullAway
        at com.google.errorprone.ErrorProneAnalyzer.lambda$scansPlugins$0(ErrorProneAnalyzer.java:85)
        at com.google.common.base.Suppliers$NonSerializableMemoizingSupplier.get(Suppliers.java:181)
        at com.google.errorprone.ErrorProneAnalyzer.finished(ErrorProneAnalyzer.java:156)
        at jdk.compiler/com.sun.tools.javac.api.MultiTaskListener.finished(MultiTaskListener.java:133)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1436)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1383)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:963)
        at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:319)
        at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:178)
        at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:64)
        at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:50)
Caused by: com.google.errorprone.scanner.ErrorProneInjector$ProvisionException: Failed to initialize com.uber.nullaway.NullAway
        at com.google.errorprone.scanner.ErrorProneInjector.getInstance(ErrorProneInjector.java:92)
        at com.google.errorprone.scanner.ErrorProneInjector.getInstance(ErrorProneInjector.java:65)
        at com.google.errorprone.scanner.ScannerSupplierImpl.instantiateChecker(ScannerSupplierImpl.java:66)
        at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
        at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:1024)
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
        at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
        at com.google.errorprone.scanner.ScannerSupplierImpl.get(ScannerSupplierImpl.java:74)
        at com.google.errorprone.scanner.ScannerSupplierImpl.get(ScannerSupplierImpl.java:37)
        at com.google.errorprone.ErrorProneAnalyzer.lambda$scansPlugins$0(ErrorProneAnalyzer.java:80)
        ... 10 more
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:74)
        at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:502)
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:486)
        at com.google.errorprone.scanner.ErrorProneInjector.getInstance(ErrorProneInjector.java:90)
        ... 22 more
Caused by: java.lang.NoClassDefFoundError: org/checkerframework/nullaway/dataflow/cfg/node/NodeVisitor
        at com.uber.nullaway.handlers.Handlers.buildDefault(Handlers.java:67)
        at com.uber.nullaway.NullAway.<init>(NullAway.java:291)
        at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62)
        ... 25 more
Caused by: java.lang.ClassNotFoundException: org.checkerframework.nullaway.dataflow.cfg.node.NodeVisitor
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:593)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
        ... 28 more

执行脚本 #

EP_VERSION=2.23.0
DATAFLOW_VERSION=3.39.0-eisop1
NULLAWAY_VERSION=0.10.15
JSPECIFY_VERSION=1.0.0

# check if downloaded, if not, download
error_prone_core_jar=error_prone_core-${EP_VERSION?}-with-dependencies.jar
dataflow_errorprone_jar=dataflow-errorprone-${DATAFLOW_VERSION?}.jar
nullaway_jar=nullaway-${NULLAWAY_VERSION?}.jar
jspecify_jar=jspecify-${JSPECIFY_VERSION?}.jar

if [ ! -f $error_prone_core_jar ]; then
    wget https://repo1.maven.org/maven2/com/google/errorprone/error_prone_core/${EP_VERSION?}/$error_prone_core_jar
fi
if [ ! -f $dataflow_errorprone_jar ]; then
    wget https://repo1.maven.org/maven2/io/github/eisop/dataflow-errorprone/${DATAFLOW_VERSION?}/$dataflow_errorprone_jar
fi
if [ ! -f $nullaway_jar ]; then
    wget https://repo1.maven.org/maven2/com/uber/nullaway/nullaway/${NULLAWAY_VERSION?}/$nullaway_jar
fi
if [ ! -f $jspecify_jar ]; then
    wget https://repo1.maven.org/maven2/org/jspecify/jspecify/${JSPECIFY_VERSION?}/$jspecify_jar
fi

echo "Jar files downloaded"

javac \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED \
  -J--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED \
  -J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED \
  -J--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED \
  -XDcompilePolicy=simple \
  -cp .:$jspecify_jar \
  -processorpath $error_prone_core_jar:$nullaway_jar:$dataflow_errorprone_jar \
  '-Xplugin:ErrorProne -XepOpt:NullAway:AnnotatedPackages=com.uber -Xep:CollectionIncompatibleType:ERROR' \
  com/uber/mylib/ShortSet.java

echo "Compilation finished"

待检测代码（com/uber/mylib/ShortSet.java） #

package com.uber.mylib;

import org.jspecify.annotations.Nullable;

/**
 * A sample class.
 */
public class ShortSet {

  static void log(Object x) {
    System.out.println(x.toString());
  }

  static void foo() {
    log(null);
  }
}

Java版本 #

$ java --version
openjdk 21.0.4 2024-07-16
OpenJDK Runtime Environment (build 21.0.4+7-Ubuntu-1ubuntu222.04)
OpenJDK 64-Bit Server VM (build 21.0.4+7-Ubuntu-1ubuntu222.04, mixed mode, sharing)

1. 依赖版本不兼容：使用的NullAway 0.10.15与Eisop Dataflow 3.39.0-eisop1版本不匹配，NullAway无法找到所需的Dataflow框架类org.checkerframework.nullaway.dataflow.cfg.node.NodeVisitor。
2. Java版本过高：NullAway 0.10.15对Java 21的支持不完善，旧版本未适配Java 21的类加载和编译器API变化，加剧了初始化失败问题。

1. 升级到兼容的依赖版本 #

使用支持Java 21的NullAway新版本，搭配对应的Error Prone和Eisop Dataflow版本，修改脚本中的版本变量：

EP_VERSION=2.26.0
DATAFLOW_VERSION=3.42.0-eisop1
NULLAWAY_VERSION=0.10.20
JSPECIFY_VERSION=1.0.0

2. 重新下载依赖jar包 #

删除旧的jar文件，运行脚本重新下载匹配版本的依赖。

3. 执行编译检测 #

运行更新后的脚本，NullAway将成功初始化并检测到代码中的NPE问题，预期输出：

error: [NullAway] passing @Nullable expression where @NonNull is required
    log(null);
        ^
    (see http://errorprone.info/bugpattern/NullAway)

内容的提问来源于stack exchange，提问作者Ziao Li