#69 Loading classes that redefine JDK classes

[Mohsen Vakilian]

WALA CAst throws an exception like the following when run on a project that redefines a JDK class. Please see the attachment for an example of a Java project on which WALA fails with the following exception.

edu.illinois.keshmesh.detector.exception.Exceptions$WALAInitializationException: java.lang.ClassCastException: com.ibm.wala.classLoader.ShrikeClass cannot be cast to com.ibm.wala.cast.java.loader.JavaSourceLoaderImpl$JavaClass
at edu.illinois.keshmesh.detector.Main.initAnalysis(Main.java:60)
at edu.illinois.keshmesh.detector.Main.initAndPerformAnalysis(Main.java:40)
at edu.illinois.keshmesh.ui.findbugs.KeshmeshFindBugsDetector.visitClassContext(KeshmeshFindBugsDetector.java:80)
at edu.umd.cs.findbugs.DetectorToDetector2Adapter.visitClass(DetectorToDetector2Adapter.java:74)
at edu.umd.cs.findbugs.FindBugs2.analyzeApplication(FindBugs2.java:1109)
at edu.umd.cs.findbugs.FindBugs2.execute(FindBugs2.java:266)
at de.tobject.findbugs.builder.FindBugsWorker.runFindBugs(FindBugsWorker.java:288)
at de.tobject.findbugs.builder.FindBugsWorker.work(FindBugsWorker.java:198)
at de.tobject.findbugs.actions.FindBugsAction$StartedFromViewJob.runWithProgress(FindBugsAction.java:265)
at de.tobject.findbugs.FindBugsJob.run(FindBugsJob.java:61)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
Caused by: java.lang.ClassCastException: com.ibm.wala.classLoader.ShrikeClass cannot be cast to com.ibm.wala.cast.java.loader.JavaSourceLoaderImpl$JavaClass
at com.ibm.wala.cast.java.loader.JavaSourceLoaderImpl.defineField(JavaSourceLoaderImpl.java:444)
at com.ibm.wala.cast.java.translator.JavaCAst2IRTranslator.defineField(JavaCAst2IRTranslator.java:229)
at com.ibm.wala.cast.ir.translator.AstTranslator.leaveFieldEntity(AstTranslator.java:2371)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitEntities(CAstVisitor.java:145)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitScopedEntities(CAstVisitor.java:122)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitScopedEntities(CAstVisitor.java:114)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitEntities(CAstVisitor.java:158)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitScopedEntities(CAstVisitor.java:122)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitScopedEntities(CAstVisitor.java:114)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitEntities(CAstVisitor.java:158)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitScopedEntities(CAstVisitor.java:122)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitScopedEntities(CAstVisitor.java:114)
at com.ibm.wala.cast.tree.visit.CAstVisitor.visitEntities(CAstVisitor.java:138)
at com.ibm.wala.cast.ir.translator.AstTranslator.walkEntities(AstTranslator.java:3611)
at com.ibm.wala.cast.ir.translator.AstTranslator.translate(AstTranslator.java:3682)
at com.ibm.wala.cast.java.translator.JavaCAst2IRTranslator.translate(JavaCAst2IRTranslator.java:51)
at com.ibm.wala.cast.java.translator.Java2IRTranslator.translate(Java2IRTranslator.java:76)
at com.ibm.wala.cast.java.translator.jdt.JDTSourceModuleTranslator$1.acceptAST(JDTSourceModuleTranslator.java:148)
at org.eclipse.jdt.core.dom.CompilationUnitResolver.resolve(CompilationUnitResolver.java:883)
at org.eclipse.jdt.core.dom.CompilationUnitResolver.resolve(CompilationUnitResolver.java:577)
at org.eclipse.jdt.core.dom.ASTParser.createASTs(ASTParser.java:888)
at com.ibm.wala.cast.java.translator.jdt.JDTSourceModuleTranslator.loadAllSources(JDTSourceModuleTranslator.java:140)
at com.ibm.wala.cast.java.loader.JavaSourceLoaderImpl.loadAllSources(JavaSourceLoaderImpl.java:428)
at com.ibm.wala.classLoader.ClassLoaderImpl.init(ClassLoaderImpl.java:478)
at com.ibm.wala.cast.java.translator.jdt.JDTClassLoaderFactory.makeNewClassLoader(JDTClassLoaderFactory.java:67)
at com.ibm.wala.classLoader.ClassLoaderFactoryImpl.getLoader(ClassLoaderFactoryImpl.java:68)
at com.ibm.wala.ipa.cha.ClassHierarchy.(ClassHierarchy.java:229)
at com.ibm.wala.ipa.cha.ClassHierarchy.(ClassHierarchy.java:175)
at com.ibm.wala.ipa.cha.ClassHierarchy.make(ClassHierarchy.java:1172)
at com.ibm.wala.cast.java.client.JavaSourceAnalysisEngine.buildClassHierarchy(JavaSourceAnalysisEngine.java:130)
at com.ibm.wala.client.AbstractAnalysisEngine.defaultCallGraphBuilder(AbstractAnalysisEngine.java:292)
at com.ibm.wala.client.AbstractAnalysisEngine.buildDefaultCallGraph(AbstractAnalysisEngine.java:301)
at edu.illinois.keshmesh.detector.Main.initAnalysis(Main.java:53)
... 10 more

[Mohsen Vakilian]

An example Java program that redefines java.util.LinkedList.

[Mohsen Vakilian]

The following patch for com.ibm.wala.core seems to fix this problem but it doesn't follow the Java's specification of the order of loading classes (See http://download.oracle.com/javase/tutorial/ext/basics/load.html\). Therefore, I believe that WALA's source loader needs to be fixed in order to address this issue properly.

Index: src/com/ibm/wala/classLoader/ClassLoaderImpl.java

--- src/com/ibm/wala/classLoader/ClassLoaderImpl.java (revision 4020)
+++ src/com/ibm/wala/classLoader/ClassLoaderImpl.java (working copy)
@@ -554,16 +554,21 @@
return arrayClassLoader.lookupClass(className, this, cha);
}

- // try delegating first.
+ // First, try our own namespace.
+ IClass result = loadedClasses.get(className);
+
+ if (result != null) {
+ return result;
+ }
+
+ // Second, try delegation.
IClassLoader parent = getParent();
if (parent != null) {
- IClass result = parent.lookupClass(className);
+ result = parent.lookupClass(className);
if (result != null) {
return result;
}
}
- // delegating failed. Try our own namespace.
- IClass result = loadedClasses.get(className);
return result;
}