Runtime error NoSuchMethodError

Question

import java.io.*;

public class SuperNotSerial {
public static void main(String[] args) {
    Dog d = new Dog(35, "Fido");
    System.out.println("before: " + d.name + " " + d.weight);
    try {
        FileOutputStream fs = new FileOutputStream("testSer.ser");
        ObjectOutputStream os = new ObjectOutputStream(fs);
        os.writeObject(d);
        os.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    try {
        FileInputStream fis = new FileInputStream("testSer.ser");
        ObjectInputStream ois = new ObjectInputStream(fis);
        d = (Dog) ois.readObject();
        ois.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    System.out.println("after: " + d.name + " " + d.weight);
}
}

class Dog extends Animal implements Serializable {
String name;

Dog(int w, String n) {
    weight = w; // inherited
    name = n; // not inherited
}
}

class Animal { // not serializable !
int weight = 42;
}

the error which is coming is.

This error is compilation error and i am not able to understand exact reason

Exception in thread "main" java.lang.NoSuchMethodError: Dog.<init>        (ILjava/lang/String;)V
at SuperNotSerial.main(SuperNotSerial.java:5)

Works for me too. I get this out put before: Fido 35 after: Fido 42 — Nargis, Jun 13 '13 at 06:03
Exception in thread “main” java.lang.NoSuchMethodError: main.. was earlier discussed at : http://stackoverflow.com/a/3540095/1882833 — Tauri, Jun 13 '13 at 06:16

score 1 · Accepted Answer · edited Nov 13 '17 at 09:18

1

Adding to fge answer that you are missing a no argument constructor required for serialization.

To know the need for a no-argument constructor while serialization we need to understand the process in which serialization takes place. Serialization works by chaining up each class in the inheritance hierarchy and then saving the state of each superclass until the first non-serialization class is reached.

Now, when we try to deserialize the object, the state of the non-serializable super class (which is required to construct the exact state of the object) can not be restored from the stream, and is instead restored by invoking the no-arg constructor.

The problem arises when the no-arg constructor of the first non-serializable class is not accessible, throwing an exception 'InvalidClassException: no valid constructor'.

As we know by default each Java class has a no-arg constructor. So, how can it be inaccessible some times?

The answer is: the default no-arg constructor is invoked only if no other constructor with arguments is declared in the class. In this case, in order to invoke the no-arg constructor we need to declare it separately.

edited Nov 13 '17 at 09:18

Tillmann

149
7

answered Jun 13 '13 at 06:02

Juned Ahsan

67,789
12
98
136

no man if we dont declare no arg constructor the system creates itself. now the program is working. – Monis Jun 13 '13 at 06:09
@Monis there is no default no-arg constructor if you define _at least_ an alternate constructor. _Please_ fix the question with the exact code, where `Animal` and `Dog` are (same file? different files?) etc. It is obvious that the code you pasted is NOT the one you ran which raised the error. – fge Jun 13 '13 at 06:12
guys i think it was some problem with my eclipse now the code is working fine..... @fge this is the same code on which i got error – Monis Jun 13 '13 at 06:18
@Juned Ahsan the super class which is not serializable need to have no arg constructor – Monis Jun 13 '13 at 06:24
No-arg constructor is not required for serialization. See http://www.javaspecialists.eu/archive/Issue175.html – Guillaume Darmont Jun 13 '13 at 06:28

Runtime error NoSuchMethodError

1 Answers1