Check if an element exists in TreeSet in Java

How to search for objects stored in a TreeSet? ArrayList implements the java.util.List which provides the get(int index) to retrieve an object with its index. Unlike List, TreeSet implements the interface java.util.Set which does not allow indexing of objects, so it cannot be accessed directly.

However, the two collections share the contains() to check if the list (in our case TreeSet) contains a specific element. You can browse TreeSet with Iterator and test equality with the condition if(o1.equals(o2)) until it reaches the desired element. Here we are talking about Set, so the elements are mixed and don't have a precise index.

import java.util.Iterator; 
import java.util.TreeSet; 

public class search_element {
 public static void main(String[] args) {
 // creating TreeSet
 TreeSet  tset = new TreeSet(); 
 
 // populate TreeSet
 tset.add("abc"); 
 tset.add("bcd"); 
 tset.add("cde"); 
 tset.add("def"); 
 tset.add("efg"); 
 
 String e = "def"; 
 
 // check for the existence of a specific element in TreeSet
 boolean exists = tset.contains(e); 
 System.out.println(e+" exists in treeset? "+exists); 
 
 String e2 = "eee"; 
 exists = tset.contains(e2); 
 System.out.println(e2+" exists in treeset? "+exists); 
 
 Iterator iterator = tset.iterator(); 
 // search for the element and test equality with equals
 while (iterator.hasNext()){
 String obj = iterator.next(); 
 if(obj.equals(e))
 System.out.println("the object "+e+" exists in the list"); 
 }
 } 
}

Compiling and executing this code results in this:

def exists in treeset? true
eee exists in treeset? false
the def object exists in the list

References:
StackOverFlow: How come Java's TreeSet has no get() method?

Check if an element exists in TreeSet in Java

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