code: private void throwExIntParam(MethodVisitor mv, Class<?> exCls) {
  		String exSig = Type.getInternalName(exCls);
  		mv.visitTypeInsn(NEW, exSig);
  		mv.visitInsn(DUP);
  		mv.visitLdcInsn("mapping " + this.className + " failed to map field:");
  		mv.visitVarInsn(ILOAD, 2);
  		mv.visitMethodInsn(INVOKESTATIC, "java/lang/Integer", "toString", "(I)Ljava/lang/String;");
  		mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/String", "concat", "(Ljava/lang/String;)Ljava/lang/String;");
  		mv.visitMethodInsn(INVOKESPECIAL, exSig, "<init>", "(Ljava/lang/String;)V");
  		mv.visitInsn(ATHROW);
  	}
docs: add Throws statement with int param 2