package bcelifier; import org.apache.commons.bcel6.generic.*; import org.apache.commons.bcel6.classfile.*; import org.apache.commons.bcel6.*; import java.io.*; public class NullCreator implements Constants { private InstructionFactory _factory; private ConstantPoolGen _cp; private ClassGen _cg; public NullCreator() { _cg = new ClassGen("bcelifier.Null", "java.lang.Object", "Null.java", ACC_PUBLIC | ACC_SUPER, new String[] { }); _cp = _cg.getConstantPool(); _factory = new InstructionFactory(_cg, _cp); } public void create(OutputStream out) throws IOException { createFields(); createMethod_0(); _cg.getJavaClass().dump(out); } private void createFields() { FieldGen field; field = new FieldGen(0, new ObjectType("java.lang.Integer"), "i", _cp); _cg.addField(field.getField()); } private void createMethod_0() { InstructionList il = new InstructionList(); MethodGen method = new MethodGen(ACC_PUBLIC, Type.VOID, Type.NO_ARGS, new String[] { }, "", "bcelifier.Null", il, _cp); InstructionHandle ih_0 = il.append(_factory.createLoad(Type.OBJECT, 0)); il.append(_factory.createInvoke("java.lang.Object", "", Type.VOID, Type.NO_ARGS, Constants.INVOKESPECIAL)); InstructionHandle ih_4 = il.append(_factory.createLoad(Type.OBJECT, 0)); il.append(InstructionConstants.ACONST_NULL); il.append(_factory.createFieldAccess("bcelifier.Null", "i", new ObjectType("java.lang.Integer"), Constants.PUTFIELD)); InstructionHandle ih_9 = il.append(_factory.createReturn(Type.VOID)); method.setMaxStack(); method.setMaxLocals(); _cg.addMethod(method.getMethod()); il.dispose(); } public static void main(String[] args) throws Exception { bcelifier.NullCreator creator = new bcelifier.NullCreator(); creator.create(new FileOutputStream("bcelifier.Null.class")); } }