I don't know if this is your problem, but your code certainly won't work for
constructors as the call to the super class constructor needs to come first.
----- Original Message -----
From: "Eduardo Guerra" <[EMAIL PROTECTED]>
To: <bcel-user@jakarta.apache.org>
Sent: Friday, April 18, 2008 12:37 PM
Subject: NullPointerException in setMaxStack()
Hi!
I'm trying to put some code for log each line of code: There is the code:
ClassParser cp = new ClassParser(new
ByteArrayInputStream(classFileBuffer),className+".java");
JavaClass jc = cp.parse();
ClassGen cg = new ClassGen(jc);
InstructionFactory factory = new InstructionFactory(cg);
ConstantPoolGen cpg = new ConstantPoolGen(jc.getConstantPool());
ObjectType pStream = new ObjectType("java.io.PrintStream");
for(int i = 0; i < cg.getMethods().length; i++){
MethodGen mg = new MethodGen(cg.getMethods()[i], jc.getClassName(), cpg);
InstructionList il = mg.getInstructionList();
for(LineNumberGen lng : mg.getLineNumbers()){
InstructionHandle ih = lng.getInstruction();
ih = il.append(ih,factory.createFieldAccess("java.lang.System",
"out", pStream, Constants.GETSTATIC));
ih = il.append(ih,new PUSH(cpg,"Classe "+jc.getClassName()+ "
metodo " + cg.getMethods()[i].getName() + " linha " +
lng.getSourceLine()));
ih = il.append(ih,factory.createInvoke("java.io.PrintStream",
"println", Type.VOID, new Type[]{Type.STRING},
Constants.INVOKEVIRTUAL));
}
mg.setInstructionList(il);
mg.setMaxStack();
mg.setMaxLocals();
cg.replaceMethod(cg.getMethods()[i], mg.getMethod());
}
cg.setConstantPool(cpg);
JavaClass newClass = cg.getJavaClass();
return newClass.getBytes();
For some methods, the setMaxStack() throws NullPointerException with
this stacktrace:
java.lang.NullPointerException
at
org.apache.bcel.generic.FieldOrMethod.getSignature(FieldOrMethod.java:54)
at
org.apache.bcel.generic.FieldInstruction.getFieldType(FieldInstruction.java:71)
at
org.apache.bcel.generic.FieldInstruction.getType(FieldInstruction.java:64)
at
org.apache.bcel.generic.FieldInstruction.getFieldSize(FieldInstruction.java:57)
at org.apache.bcel.generic.GETSTATIC.produceStack(GETSTATIC.java:47)
at org.apache.bcel.generic.MethodGen.getMaxStack(MethodGen.java:928)
at org.apache.bcel.generic.MethodGen.setMaxStack(MethodGen.java:814)
at teste.IntrumentatorAdaptor.transform(IntrumentatorAdaptor.java:54)
at
sun.instrument.TransformerManager.transform(TransformerManager.java:169)
at
sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:365)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
Thanks in advance for any help!!!
Eduardo Guerra
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