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Java ObjectInputStream readLong() Method with Example

ObjectInputStream Class readLong() method: Here, we are going to learn about the readLong() method of ObjectInputStream Class with its syntax and example.
Submitted by Preeti Jain, on April 04, 2020

ObjectInputStream Class readLong() method

• readLong() method is available in java.io package.
• readLong() method is used to read 8 bytes (i.e. 64 bit) of long value from this ObjectInputStream stream.
• readLong() 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.
• readLong() method may throw an exception at the time of reading long.
  • IOException: This exception may throw when getting any input/output error while performing.
  • EOFException: This exception may throw when this stream has reached its end of the file.

Syntax:

    public long readLong();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is long, it returns the 8 bytes long value read.

Example:

// Java program to demonstrate the example 
// of long readLong() method of ObjectInputStream

import java.io.*;

public class ReadLongOfOIS {
 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 writeLong() method is to write
  // long to the obj_out_stm stream
  obj_out_stm.writeLong(5411489332534l);
  obj_out_stm.writeLong(234773224114l);

  obj_out_stm.flush();

  while (obj_in_stm.available() > 0) {
   // By using readLong() method is to read
   //  long from the obj_in_stm
   long val = (int) obj_in_stm.readLong();
   System.out.println("obj_in_stm.readLong(): " + val);
  }

  // By using close() method is to 
  // close all the streams 
  file_in_stm.close();
  file_out_stm.close();
  obj_in_stm.close();
  obj_out_stm.close();
 }
}

Output

obj_in_stm.readLong(): -169460426
obj_in_stm.readLong(): -1449977166