In this article, we will see how to implement random sleep in Java which helps to avoid synchronization issues and make the behaviour of concurrent programs less predictable.

Using the java.util.Random class, we can generate random values and these random values can be passed to the sleep method as a duration to achieve the random sleep.

Using a Random class to generate a number

To begin, we need to import the Random class into our Java program as shown below.

import java.util.Random;

Now, we need to create an instance of Random class to generate random numbers.

Random random = new Random();

Using the random object, we can generate a random sleep duration by calling the nextInt() method. This method returns a random integer within a specified range.

To create a random sleep duration between a minimum and maximum value, we can calculate the difference between the maximum and minimum values and add it to the minimum value.

int minDuration = 1000; // Minimum sleep duration in milliseconds
int maxDuration = 5000; // Maximum sleep duration in milliseconds

int randomDuration = minDuration + random.nextInt(maxDuration - minDuration + 1);

Putting a thread to sleep

We have a sleep value now with randomly generated duration and by using the Thread.sleep() method we can make the thread sleep. This thread accepts the sleep duration in milliseconds. Pass the randomly generated value to the thread to make the thread sleep for a random duration.

Following is the example:

try {
} catch (InterruptedException e) {


Q: Can I use the same random instance for multiple sleep durations?

A: Yes, you can reuse the same instance of Random to generate multiple random numbers. Creating a new instance for each sleep duration is not necessary.

Q: Are there any considerations for using random sleep durations in multi-threaded applications?

A: When using random sleep durations in multi-threaded applications, ensure proper synchronization and coordination mechanisms to avoid conflicts or race conditions among threads.

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