Java Random.next() – Syntax & Examples

Java Random.next() – Examples

In this tutorial, we will learn about the Java Random.next() method, and learn how to use this method to get a pseudorandom number, with the help of examples.

next(int bits)

Random.next() returns the next pseudorandom number from this Random Generator’s sequence.

Syntax

The syntax of next() method is

Random.next(int bits)

where

Parameter	Description
bits	The number of bits that will be considered for random number.

Returns

The method returns protected integer.

Example 1 – next(bits)

Random.next() is a protected method of Random class. So, to use this class, we may have to create a class, say Example with Random as its parent class. Since, Example is a child class of Random, Example can access protected class of Random.

Java Program

import java.util.Random;

public class Example extends Random{ 
    public static void main(String[] args) {
    	Example random = new Example();
		System.out.println(" Next Random Value : " + random.next(9));
		System.out.println(" Next Random Value : " + random.next(15));  
		System.out.println(" Next Random Value : " + random.next(32));  
		System.out.println(" Next Random Value : " + random.next(4));
    }
}

Output

 Next Random Value : 174
 Next Random Value : 10188
 Next Random Value : -776918100
 Next Random Value : 9

Output may vary, since the numbers are generated randomly.

Example 2 – next(bits) – bits = 1

In this example, we will give next() an argument of 1. So, only one bit is used to generate the resulting random number.

We will call next(1) in a loop, so that, we can observe what next(1) returns for multiple runs.

Java Program

import java.util.Random;

public class Example extends Random{ 
    public static void main(String[] args) {
    	Example random = new Example();
    	for(int i=0; i < 25; i++)
    		System.out.println(random.next(1));
    }
}

Output

1
0
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
0
1
1
0
0
0
0
1

With one bit, we could only get either 0 or 1.

Output may vary, since the numbers are generated randomly.

Example 3 – next(bits) – bits = 3

In this example, we will give next() an argument of 3. So, only three bits are used to generate the resulting random number. So, the next() should return a value in between 0 and 7, including these.

Java Program

import java.util.Random;

public class Example extends Random{ 
    public static void main(String[] args) {
    	Example random = new Example();
    	for(int i=0; i < 25; i++)
    		System.out.println(random.next(3));
    }
}

Output

2
0
4
3
2
0
1
7
5
5
2
7
4
6
0
1
6
4
1
3
3
0
6
4
0

Output may vary, since the numbers are generated randomly.

Conclusion

In this Java Tutorial, we have learnt the syntax of Java Random.next() method, and also learnt how to use this method with the help of examples.