Java - ObjectInputStream readBoolean() method

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Description

The Java ObjectInputStream readBoolean() method reads a single boolean value (true or false) from the stream. It is used when a boolean value has been written using writeBoolean(boolean b).

Declaration

Following is the declaration for java.io.ObjectInputStream.readBoolean() method −

public boolean readBoolean()

Parameters

NA

Return Value

This method returns the boolean read.

Exception

• EOFException − If end of file is reached.

• IOException − If an I/O error has occurred.

Example - Usage of ObjectInputStream readBoolean() method

The following example shows the usage of Java ObjectInputStream readBoolean() method.

ObjectInputStreamDemo.java

package com.tutorialspoint;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class ObjectInputStreamDemo {
   public static void main(String[] args) {
      try {
         // create a new file with an ObjectOutputStream
         FileOutputStream out = new FileOutputStream("test.txt");
         ObjectOutputStream oout = new ObjectOutputStream(out);

         // write something in the file
         oout.writeBoolean(true);
         oout.flush();

         // create an ObjectInputStream for the file we created before
         ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.txt"));

         // read and print a boolean
         System.out.println("" + ois.readBoolean());
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}

Output

Let us compile and run the above program, this will produce the following result−

true

Example - Writing and Reading a Boolean Value

The following example shows the usage of Java ObjectInputStream readBoolean() method. This example writes a single boolean value to a file and reads it using readBoolean().

ObjectInputStreamDemo.java

package com.tutorialspoint;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class ObjectInputStreamDemo {
   public static void main(String[] args) {
      try {
         // Writing a boolean value to a file
         FileOutputStream fos = new FileOutputStream("boolean_data.dat");
         ObjectOutputStream oos = new ObjectOutputStream(fos);
         oos.writeBoolean(true); // Writing 'true'
         oos.close();

         // Reading boolean value using ObjectInputStream
         FileInputStream fis = new FileInputStream("boolean_data.dat");
         ObjectInputStream ois = new ObjectInputStream(fis);

         boolean value = ois.readBoolean(); // Read boolean value
         System.out.println("Read Boolean Value: " + value);

         ois.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Output

Let us compile and run the above program, this will produce the following result−

Read Boolean Value: true

Explanation

• Writes true to the file using writeBoolean(true).

• Reads the boolean value using readBoolean().

• Prints the value, confirming that true was correctly stored and retrieved.

Example - Writing and Reading Multiple Boolean Values

The following example shows the usage of Java ObjectInputStream readBoolean() method. This example writes multiple boolean values (true and false) and reads them sequentially.

ObjectInputStreamDemo.java

package com.tutorialspoint;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class ObjectInputStreamDemo {
   public static void main(String[] args) {
      try {
         // Writing multiple boolean values
         FileOutputStream fos = new FileOutputStream("multiple_booleans.dat");
         ObjectOutputStream oos = new ObjectOutputStream(fos);
         oos.writeBoolean(true);
         oos.writeBoolean(false);
         oos.writeBoolean(true);
         oos.close();

         // Reading boolean values using ObjectInputStream
         FileInputStream fis = new FileInputStream("multiple_booleans.dat");
         ObjectInputStream ois = new ObjectInputStream(fis);

         System.out.println("First Boolean: " + ois.readBoolean());
         System.out.println("Second Boolean: " + ois.readBoolean());
         System.out.println("Third Boolean: " + ois.readBoolean());

         ois.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Output

Let us compile and run the above program, this will produce the following result−

First Boolean: true
Second Boolean: false
Third Boolean: true

Explanation

• Writes three boolean values (true, false, true) to a file.

• Reads them one by one using readBoolean(), maintaining the original order.

• Prints each boolean value, confirming correct serialization and deserialization.