java.lang.RuntimeException: wrong class format Caused by: org.eclipse.jdt.internal.compiler.classfmt.ClassFormatException: null

Spring Boot 启动的时候报的错

使用Drools 5.6版本，Spring Boot1.5.8版本，JAVA8版本，Eclipse4.4.2版本。

Google后在Stack上发现一个，中文较少，贴一下。

原因是因为Eclipse不支持Java8编译Drools5.6版本。

解决方案：

给项目添加依赖：

<dependency>
            <groupId>org.eclipse.jdt.core.compiler</groupId>
            <artifactId>ecj</artifactId>
            <version>4.5.1</version>
</dependency>

再次启动，OK

报错内容：

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'knowledgeBase': Invocation of init method failed; nested exception is java.lang.RuntimeException: wrong class format
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$.getObject(AbstractBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    ...  common frames omitted
Caused by: java.lang.RuntimeException: wrong class format
    at org.drools.commons.jci.compilers.EclipseJavaCompiler$.findType(EclipseJavaCompiler.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.commons.jci.compilers.EclipseJavaCompiler$.findType(EclipseJavaCompiler.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.askForType(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.UnresolvedReferenceBinding.resolve(UnresolvedReferenceBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.resolveType(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.getTypeFromTypeSignature(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.getTypeFromVariantTypeSignature(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.getTypeArgumentsFromSignature(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.getTypeFromTypeSignature(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.createMethod(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.createMethods(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.cachePartsFrom(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.createBinaryTypeFrom(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.createBinaryTypeFrom(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.Compiler.accept(Compiler.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.askForType(LookupEnvironment.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.UnresolvedReferenceBinding.resolve(UnresolvedReferenceBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.resolveType(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.ParameterizedTypeBinding.resolve(ParameterizedTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.resolveType(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.resolveTypesFor(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.getExactMethod(BinaryTypeBinding.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.Scope.findExactMethod(Scope.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.lookup.Scope.getMethod(Scope.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.Expression.resolve(Expression.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:) ~[ecj-3.5..jar:na]
    at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:) ~[ecj-3.5..jar:na]
    at org.drools.commons.jci.compilers.EclipseJavaCompiler.compile(EclipseJavaCompiler.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.commons.jci.compilers.AbstractJavaCompiler.compile(AbstractJavaCompiler.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.rule.builder.dialect.java.JavaDialect.compileAll(JavaDialect.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.DialectCompiletimeRegistry.compileAll(DialectCompiletimeRegistry.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.PackageRegistry.compileAll(PackageRegistry.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.PackageBuilder.compileAll(PackageBuilder.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.PackageBuilder.compileAllRules(PackageBuilder.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.PackageBuilder.addPackageFromDecisionTable(PackageBuilder.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.container.spring.beans.KnowledgeBaseBeanFactory.afterPropertiesSet(KnowledgeBaseBeanFactory.java:) ~[drools-spring-5.6..Final.jar:5.6..Final]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:) ~[spring-beans-4.3..RELEASE.jar:4.3..RELEASE]
    ...  common frames omitted
Caused by: org.eclipse.jdt.internal.compiler.classfmt.ClassFormatException: null
    at org.eclipse.jdt.internal.compiler.classfmt.ClassFileReader.<init>(ClassFileReader.java:) ~[ecj-3.5..jar:na]
    at org.drools.commons.jci.compilers.EclipseJavaCompiler$.createNameEnvironmentAnswer(EclipseJavaCompiler.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    at org.drools.commons.jci.compilers.EclipseJavaCompiler$.findType(EclipseJavaCompiler.java:) ~[drools-compiler-5.6..Final.jar:5.6..Final]
    ...  common frames omitted