Drools：编译规则（或加载编译规则）失败，在JamVM中出现模糊异常

我正在开发一个框架，作为其功能之一，它使机器人能够使用基于规则的系统。我们从Jess开始是RBS，现在想要实现drools（使用drools 5.2.0 final），它可以在运行OpenJDK 6的开发机器上运行

我们的robot控制器运行armlinux和JamVM，以前是1.4.3，但我最近编译了1.5.4，因为它缺少drools所需的类。失败后，我在虚拟机中使用与为控制器编译JAMV时相同的配置安装了JAMV，在那里它失败了，出现了相同的异常

一些研究表明，Drools+JamVM有bug报告，但这也意味着它通常可以工作

---

使用预编译规则和以下代码运行框架时

kBase = KnowledgeBaseFactory.newKnowledgeBase();

ObjectInputStream in;
Collection<KnowledgePackage> kpkgs;
try {
    in = new ObjectInputStream(Thread.currentThread().getContextClassLoader().getResourceAsStream(
            packageFile));
    kpkgs = (Collection<KnowledgePackage>) in.readObject();
    in.close();
} catch(IOException e) {
    throw new DisboticsException("Couldn't read drools knowledge package file!", e);
} catch(ClassNotFoundException e) {
    throw new DisboticsException("Drools knowledge package file didn't contain expected instance.", e);
}

kBase.addKnowledgePackages(kpkgs);
kSession = kBase.newStatefulKnowledgeSession();

…在OpenJDK中工作。奇怪的是，

javadialtruntimedata

中有问题的列表是通过

Collections.emptyList（）

获得的，并且再也不会被更改（或者eclipse建议……）

---

使用此代码运行裸

.drl

文件时：

Properties props = new Properties();
props.put("drools.dialect.java.compiler", "JANINO");

KnowledgeBuilderConfiguration kbConfig = KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration(props,
        (ClassLoader[]) null);
KnowledgeBuilder kBuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(kbConfig);

kBuilder.add(ResourceFactory.newClassPathResource("disbotics/core/rules/drools/function.drl",
        DroolsRulesPlugin.class), ResourceType.DRL);
kBuilder.add(ResourceFactory.newClassPathResource(rulesFile, DroolsRulesPlugin.class), ResourceType.DRL);

if(kBuilder.hasErrors()) {
    String errorMessage = "";
    for(KnowledgeBuilderError error:kBuilder.getErrors())
        errorMessage = errorMessage + error.getMessage() + "\n";
    throw new DisboticsException(errorMessage);
}

kBase = KnowledgeBaseFactory.newKnowledgeBase();
kBase.addKnowledgePackages(kBuilder.getKnowledgePackages());
kSession = kBase.newStatefulKnowledgeSession();

。。。我从规则编译器中获得以下（意外）异常：

Exception in thread "main" disbotics.core.common.DisboticsException: Line 2:8 unexpected exception at input '"mvel"'. Exception: java.lang.UnsupportedOperationException. Stack trace:
 java.lang.UnsupportedOperationException
   at java.util.AbstractList.add(AbstractList.java:131)
   at java.util.AbstractList.add(AbstractList.java:152)
   at org.drools.lang.descr.PackageDescr.addAttribute(PackageDescr.java:138)
   at org.drools.lang.api.impl.PackageDescrBuilderImpl.attribute(PackageDescrBuilderImpl.java:93)
   at org.drools.lang.ParserHelper.start(ParserHelper.java:684)
   at org.drools.lang.DRLParser.stringAttribute(DRLParser.java:1289)
   at org.drools.lang.DRLParser.attribute(DRLParser.java:1062)
   at org.drools.lang.DRLParser.statement(DRLParser.java:276)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:55)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

[ERR 107] Line 2:8 mismatched input '"mvel"' expecting one of the following tokens: '[package, import, global, declare, function, rule, query]'.
Line 4:0 unexpected exception at input 'global'. Exception: java.util.EmptyStackException. Stack trace:
 java.util.EmptyStackException
   at java.util.Stack.pop(Stack.java:109)
   at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:421)
   at org.drools.lang.ParserHelper.end(ParserHelper.java:732)
   at org.drools.lang.DRLParser.globalStatement(DRLParser.java:401)
   at org.drools.lang.DRLParser.statement(DRLParser.java:261)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:55)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

Parser returned a null Package
Line 2:8 unexpected exception at input '"java"'. Exception: java.lang.UnsupportedOperationException. Stack trace:
 java.lang.UnsupportedOperationException
   at java.util.AbstractList.add(AbstractList.java:131)
   at java.util.AbstractList.add(AbstractList.java:152)
   at org.drools.lang.descr.PackageDescr.addAttribute(PackageDescr.java:138)
   at org.drools.lang.api.impl.PackageDescrBuilderImpl.attribute(PackageDescrBuilderImpl.java:93)
   at org.drools.lang.ParserHelper.start(ParserHelper.java:684)
   at org.drools.lang.DRLParser.stringAttribute(DRLParser.java:1289)
   at org.drools.lang.DRLParser.attribute(DRLParser.java:1062)
   at org.drools.lang.DRLParser.statement(DRLParser.java:276)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:57)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

[ERR 107] Line 2:8 mismatched input '"java"' expecting one of the following tokens: '[package, import, global, declare, function, rule, query]'.
Line 4:0 unexpected exception at input 'import'. Exception: java.util.EmptyStackException. Stack trace:
 java.util.EmptyStackException
   at java.util.Stack.pop(Stack.java:109)
   at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:421)
   at org.drools.lang.ParserHelper.end(ParserHelper.java:732)
   at org.drools.lang.DRLParser.importStatement(DRLParser.java:349)
   at org.drools.lang.DRLParser.statement(DRLParser.java:258)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:57)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

Line 6:0 unexpected exception at input 'rule'. Exception: java.util.EmptyStackException. Stack trace:
 java.util.EmptyStackException
   at java.util.Stack.pop(Stack.java:109)
   at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:421)
   at org.drools.lang.ParserHelper.end(ParserHelper.java:732)
   at org.drools.lang.DRLParser.rule(DRLParser.java:886)
   at org.drools.lang.DRLParser.statement(DRLParser.java:267)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:57)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

Parser returned a null Package

   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:63)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

同样，在OpenJDK中编译规则工作得很好。我们使用的是Janino，它在类路径上被正确引用（运行时使用的类路径由Maven构建创建，因此包含drools/Janino/anythis引用的所有JAR）

---

---

有人知道这里发生了什么和/或如何让Drools使用JAVM吗？

您是否使用OpenJDK 1.6编译知识包？然后尝试加载1.5.4？您应该尝试使用1.5.4编译原始包，看看是否有相同的错误

对于堆栈跟踪，看起来您正在尝试将某些内容添加到不可修改的列表中，对吗

基本上，这里有一个例外：kBase.addKnowledgePackages（kpkg）；

---

是吗？

1）是的，是的-我还尝试在运行时编译规则，即使用JamVM，但这也给了我同样奇怪的错误。我也会尽快发布。。。2） 是的，是的——问题是（除非Drools在OpenJDK中不调用该代码），错误是针对JAMV的，尽管代码不建议用可修改的列表替换空列表（除非这里使用了一些高级反射），但JAMV似乎不支持不可修改的列表方法。不同的JVM实现可以忽略这类事情。我们应该多读一点关于JAVM为何抛出此异常的内容，并了解如何修复它：java.util.AbstractList.add（AbstractList.java:131）处的java.lang.UnsupportedOperationException感谢您的帮助！我希望您能找出JAVM上的列表有什么问题。在这么长的时间里，我们会尝试和Jess呆在一起，或者切换虚拟机，希望它能工作！如果您切换虚拟机但仍然存在问题，请告诉我，不支持的操作异常是虚拟机实现的一部分，因此我们应该尝试另一个。干杯

Exception in thread "main" disbotics.core.common.DisboticsException: Line 2:8 unexpected exception at input '"mvel"'. Exception: java.lang.UnsupportedOperationException. Stack trace:
 java.lang.UnsupportedOperationException
   at java.util.AbstractList.add(AbstractList.java:131)
   at java.util.AbstractList.add(AbstractList.java:152)
   at org.drools.lang.descr.PackageDescr.addAttribute(PackageDescr.java:138)
   at org.drools.lang.api.impl.PackageDescrBuilderImpl.attribute(PackageDescrBuilderImpl.java:93)
   at org.drools.lang.ParserHelper.start(ParserHelper.java:684)
   at org.drools.lang.DRLParser.stringAttribute(DRLParser.java:1289)
   at org.drools.lang.DRLParser.attribute(DRLParser.java:1062)
   at org.drools.lang.DRLParser.statement(DRLParser.java:276)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:55)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

[ERR 107] Line 2:8 mismatched input '"mvel"' expecting one of the following tokens: '[package, import, global, declare, function, rule, query]'.
Line 4:0 unexpected exception at input 'global'. Exception: java.util.EmptyStackException. Stack trace:
 java.util.EmptyStackException
   at java.util.Stack.pop(Stack.java:109)
   at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:421)
   at org.drools.lang.ParserHelper.end(ParserHelper.java:732)
   at org.drools.lang.DRLParser.globalStatement(DRLParser.java:401)
   at org.drools.lang.DRLParser.statement(DRLParser.java:261)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:55)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

Parser returned a null Package
Line 2:8 unexpected exception at input '"java"'. Exception: java.lang.UnsupportedOperationException. Stack trace:
 java.lang.UnsupportedOperationException
   at java.util.AbstractList.add(AbstractList.java:131)
   at java.util.AbstractList.add(AbstractList.java:152)
   at org.drools.lang.descr.PackageDescr.addAttribute(PackageDescr.java:138)
   at org.drools.lang.api.impl.PackageDescrBuilderImpl.attribute(PackageDescrBuilderImpl.java:93)
   at org.drools.lang.ParserHelper.start(ParserHelper.java:684)
   at org.drools.lang.DRLParser.stringAttribute(DRLParser.java:1289)
   at org.drools.lang.DRLParser.attribute(DRLParser.java:1062)
   at org.drools.lang.DRLParser.statement(DRLParser.java:276)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:57)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

[ERR 107] Line 2:8 mismatched input '"java"' expecting one of the following tokens: '[package, import, global, declare, function, rule, query]'.
Line 4:0 unexpected exception at input 'import'. Exception: java.util.EmptyStackException. Stack trace:
 java.util.EmptyStackException
   at java.util.Stack.pop(Stack.java:109)
   at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:421)
   at org.drools.lang.ParserHelper.end(ParserHelper.java:732)
   at org.drools.lang.DRLParser.importStatement(DRLParser.java:349)
   at org.drools.lang.DRLParser.statement(DRLParser.java:258)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:57)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

Line 6:0 unexpected exception at input 'rule'. Exception: java.util.EmptyStackException. Stack trace:
 java.util.EmptyStackException
   at java.util.Stack.pop(Stack.java:109)
   at org.drools.lang.ParserHelper.popParaphrases(ParserHelper.java:421)
   at org.drools.lang.ParserHelper.end(ParserHelper.java:732)
   at org.drools.lang.DRLParser.rule(DRLParser.java:886)
   at org.drools.lang.DRLParser.statement(DRLParser.java:267)
   at org.drools.lang.DRLParser.compilationUnit(DRLParser.java:155)
   at org.drools.compiler.DrlParser.compile(DrlParser.java:225)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:136)
   at org.drools.compiler.DrlParser.parse(DrlParser.java:141)
   at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:352)
   at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:538)
   at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)
   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:57)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)

Parser returned a null Package

   at disbotics.core.config.DroolsRulesPlugin.initialize(DroolsRulesPlugin.java:63)
   at disbotics.core.common.DisboticsCore.startFramework(DisboticsCore.java:109)
   at disbotics.core.common.DisboticsCore.main(DisboticsCore.java:56)