Home »
Java programming language
Java ObjectOutputStream writeObject() Method with Example
ObjectOutputStream Class writeObject() method: Here, we are going to learn about the writeObject() method of ObjectOutputStream Class with its syntax and example.
Submitted by Preeti Jain, on April 10, 2020
ObjectOutputStream Class writeObject() method
- writeObject() method is available in java.io package.
- writeObject() method is used to write the given object to the ObjectOutputStream. It includes the class, signature, values of non-static and non-transient fields of the given object of the class are written. Objects address by this object (o) are written transitively so that graph objects can be reformed by an ObjectInputStream.
- writeObject() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
-
writeObject() method may throw an exception at the time of writing an object.
- IOException: This exception may throw when getting any input/output error while writing to the output stream.
- InvalidClassException: This exception may throw when invalid things with a class used by serialization.
- NotSerializableException: This exception may throw when the serialized object does not implement the Serializable interface.
Syntax:
public final void writeObject(Object o);
Parameter(s):
- Object o – represents the object to be written.
Return value:
The return type of the method is void, it returns nothing.
Example:
// Java program to demonstrate the example
// of void writeObject(Object o) method of
// ObjectOutputStream
import java.io.*;
public class WriteObjectOfOOS {
public static void main(String[] args) throws Exception {
// Instantiates ObjectOutputStream , ObjectInputStream
// FileInputStream and FileOutputStream
FileOutputStream file_out_stm = new FileOutputStream("D:\\includehelp.txt");
ObjectOutputStream obj_out_stm = new ObjectOutputStream(file_out_stm);
FileInputStream file_in_stm = new FileInputStream("D:\\includehelp.txt");
ObjectInputStream obj_in_stm = new ObjectInputStream(file_in_stm);
// By using writeObject() method is to
// write the object to the stream
obj_out_stm.writeObject("Java");
obj_out_stm.writeObject("World");
obj_out_stm.flush();
// By using readObject() method is to
// read the object
for (int i = 0; i < 2; ++i) {
String str = (String) obj_in_stm.readObject();
System.out.println("obj_in_stm.readObject(): " + str);
}
// By using close() method is to
// close all the streams
System.out.println("Stream Shutdown... ");
file_in_stm.close();
file_out_stm.close();
obj_in_stm.close();
obj_out_stm.close();
}
}
Output
obj_in_stm.readObject(): Java
obj_in_stm.readObject(): World
Stream Shutdown...