import org.objectweb.asm.*;
public class HelloWorldGenerator {
public static void main(String[] args) throws Exception {
ClassWriter cw = new ClassWriter(0);
FieldVisitor fv;
MethodVisitor mv;
cw.visit(52, ACC_PUBLIC + ACC_SUPER, "HelloWorld", null, "java/lang/Object", null);
{
mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
mv.visitCode();
Label l0 = new Label();
mv.visitLabel(l0);
mv.visitLineNumber(3, l0);
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
mv.visitInsn(RETURN);
Label l1 = new Label();
mv.visitLabel(l1);
mv.visitLocalVariable("this", "LHelloWorld;", null, l0, l1, 0);
mv.visitMaxs(1, 1);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC, "main", "([Ljava/lang/String;)V", null, null);
mv.visitCode();
Label l0 = new Label();
mv.visitLabel(l0);
mv.visitLineNumber(6, l0);
mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
mv.visitLdcInsn("Hello, world!");
mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);
Label l1 = new Label();
mv.visitLabel(l1);
mv.visitLineNumber(7, l1);
mv.visitInsn(RETURN);
Label l2 = new Label();
mv.visitLabel(l2);
mv.visitLocalVariable("args", "[Ljava/lang/String;", null, l0, l2, 0);
mv.visitMaxs(2, 1);
mv.visitEnd();
}
cw.visitEnd();
byte[] bytes = cw.toByteArray();
try (FileOutputStream fos = new FileOutputStream("HelloWorld.class")) {
fos.write(bytes);
}
}
}
