VOOZH about

URL: https://www.geeksforgeeks.org/java/sortedset-retainall-method-in-java-with-examples/

⇱ SortedSet retainAll() method in Java with Examples - GeeksforGeeks

  • Courses
  • Tutorials
  • Interview Prep

SortedSet retainAll() method in Java with Examples

Last Updated : 12 Jul, 2025

The retainAll() method of SortedSet interface is used to retain from this SortedSet, all of its elements that are contained in the specified collection.

Syntax:  

public boolean retainAll(Collection c)

Parameters: This method takes collection c as a parameter containing elements to be retained from this SortedSet.

Return Value: This method returns true if this SortedSet changed as a result of the call.

Exception: This method throws NullPointerException if this set contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null.

Note: The retainAll() method in SortedSet is inherited from the Set interface in Java.

Below are the examples to illustrate the retainAll() method.

Example 1:  


Output: 
Set before retainAll() operation : [1, 2, 3, 4, 5]
Collection Elements to be retained : [1, 2, 3]
Set after retainAll() operation : [1, 2, 3]

 

Example 2: For NullPointerException.


Output: 
Set before retainAll() operation : [1, 2, 3, 4, 5]
Collection Elements to be retained : null

Trying to pass null as a specified element

java.lang.NullPointerException

 

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Set.html#retainAll(java.util.Collection)
 

Comment