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TreeSet pollFirst() method in Java

Last Updated : 11 Jul, 2025
The pollFirst() method of TreeSet in Java is used to retrieves and removes the first (lowest) element, or returns null if this TreeSet is empty. Syntax: 
E pollFirst()
Where, E is the type of elements maintained by this TreeSet container. Parameters: This function does not accepts any parameter. Return Type:It returns the first element of the Treeset if TreeSet is not empty else returns null. Below programs illustrate the pollFirst() method in Java: Example 1
Output: 
Before removing element from TreeSet: [0, 1, 2, 3, 4, 5, 6]
First lowest element removed is : 0
After removing element from TreeSet: [1, 2, 3, 4, 5, 6]
Example 2
Output: 
pollFirst() method when TreeSet is empty : null
Before removing element from TreeSet: [Geek, Geeks, for]
First lowest element removed is : Geek
After removing element from TreeSet: [Geeks, for]
If TreeSet is empty, then this method returns null. Example 3
Output: 
Before removing element from TreeSet: []
First lowest element removed is : null
After removing element from TreeSet: []
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