cw.visitField(Opcodes.ACC_PRIVATE, "key", "L"+qualifiedInternalKeyClassName+";", null, null);
cw.visitField(Opcodes.ACC_PRIVATE, "value", "L"+qualifiedInternalValueClassName+";", null, null);
MethodVisitor mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
mv.visitVarInsn(Opcodes.ALOAD, 0);
mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
mv.visitInsn(Opcodes.RETURN);
mv.visitMaxs(1, 1);
mv.visitEnd();