import org.apache.bcel.Const; import org.apache.bcel.generic.ClassGen; import org.apache.bcel.generic.ConstantPoolGen; import org.apache.bcel.generic.InstructionList; import org.apache.bcel.generic.MethodGen; import org.apache.bcel.generic.Type; public class BCELExample { public static void main(String[] args) { ConstantPoolGen constantPoolGen = classGen.getConstantPool(); int stringIndex = constantPoolGen.addString("Hello, BCEL!"); InstructionList instructionList = new InstructionList(); instructionList.append(new org.apache.bcel.generic.GETSTATIC(constantPoolGen.addFieldref("java.lang.System", "out", "Ljava/io/PrintStream;"))); instructionList.append(new org.apache.bcel.generic.LDC(stringIndex)); instructionList.append(new org.apache.bcel.generic.INVOKEVIRTUAL(constantPoolGen.addMethodref("java.io.PrintStream", "println", "(Ljava/lang/String;)V"))); instructionList.append(new org.apache.bcel.generic.RETURN()); methodGen.setMaxStack(); methodGen.setMaxLocals(); classGen.addMethod(methodGen.getMethod()); classGen.getJavaClass().dump("HelloWorld.class"); } }