Consumer Interface is a part of the java.util.function package which is introduced in Java 8. It is an in-built Functional Interface. This function expect an input but produces no output. In this post, we are going to see several implementations of Consumer Interface by using different examples.



Consumer Interface in Java 8 with Examples...!!! Share on X

Look at Consumer Javadoc description below:





Consumer Interface contains 2 methods:

  1. accept 

  2. andThen


Let’s discuss these methods:


This method accepts one input argument and performs operation on the given argument.



Below are the several examples to demonstrate accept() method:

Example 1. with Integer


Example 2. with HashMap


Example 3. with ArrayList using Stream API 


Example 4. with custom Class object (like ‘Students’ in this case)


Students Class:



Returns a composed Consumer that performs, in sequence, this operation followed by the after operation. If performing either operation throws an exception, it is relayed to the caller of the composed operation. If performing this operation throws an exception, the after operation will not be performed.



Below are the several examples to demonstrate andThen() method:


Example 5. with String


Example 6. with ArrayList using Stream API 


Java 8 Consumer Interface is an absolute useful addition as part of ‘Functional Interfaces’ and can serve variety of purposes. It is quite powerful as it can be used as a higher order functions through lambda functions and above examples could help you to get better idea on how to implement it.


Consumer Interface in Java 8 with Examples...!!! Share on X


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  • Deepak Verma

    Deepak Verma is a Test Automation Consultant and Software development Engineer for more than 10 years. His mission is to help you become an In-demand full stack automation tester. He is also the founder of Techndeck, a blog and online coaching platform dedicated to helping you succeed with all the automation basics to advanced testing automation tricks. Verma Deepak