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Java TreeSet contains() Method with Example

TreeSet Class contains() method: Here, we are going to learn about the contains() method of TreeSet Class with its syntax and example.
Submitted by Preeti Jain, on February 20, 2020

TreeSet Class contains() method

• contains() method is available in java.util package.
• contains() method is used to check whether the given object (ob) exists or not in this TreeSet.
• contains() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• contains() method may throw an exception at the time of checking the given object exists.
• ClassCastException: This exception may throw when the given parameter is incompatible to compare.
• NullPointerException: This exception may throw when the given parameter is null exists.

Syntax:

    public boolean contains(Object ob);

Parameter(s):

• Object ob – represents the object (ob) to be checked for existence in this TreeSet.

Return value:

The return type of the method is boolean, it returns true when the given object (ob) exists in this TreeSet otherwise it returns false.

Example:

// Java program to demonstrate the example 
// of boolean contains(Object ob) method of TreeSet 

import java.util.*;

public class ContainsOfTreeSet {
    public static void main(String[] args) {
        // Instantiates a TreeSet object
        TreeSet < String > tree_set = new TreeSet < String > ();

        // By using add() method is to add
        // the given object of this TreeSet 
        tree_set.add("C");
        tree_set.add("C++");
        tree_set.add("JAVA");
        tree_set.add("PHP");
        tree_set.add("SFDC");

        // Display TreeSet
        System.out.println("TreeSet: " + tree_set);

        // By using contains() method is to 
        // check whether the given object exists
        // or not exists in this TreeSet
        boolean status = tree_set.contains("JAVA");

        // Display Status
        System.out.println("tree_set.contains(JAVA): " + status);
    }
}

Output

TreeSet: [C, C++, JAVA, PHP, SFDC]
tree_set.contains(JAVA): true