How to fix NoSuchElementException in Java?

Constructors of NoSuchElementException

The constructors for the NoSuchElementException in Java:

These constructors allow you to create instances of NoSuchElementException with or without a custom error message.

Java util NoSuchElementException

NoSuchElementException as the name implies, is an exception that occurs when the intended element does not found. Numerous accessor methods in Java throw NoSuchElementException to indicate that the requested element does not exist. It is an Unchecked exception which means it occurs during run time. 

Let us see its hierarchy: 

Causes of java util NoSuchElementException

In Java, the java util NoSuchElementException is raised when an iterable's maximum limit gets exceeded or when there are no more enumeration elements to iterate over. 
The following causes the java util NoSuchElementException to be thrown:

iterator::next()

Enumeration::nextElement()

StringTokenizer::nextElement()

NoSuchElementException Example

Below code shows the occurrence of java util NoSuchElementException in java while using the above methods: 

• Java

Java

import java.util.*;
public class main {
    public static void main(String[] arguments) {
        HashMap<Integer, String> map = new HashMap<Integer, String>();

        // commands that throw exception. 
        Iterator itr = map.keySet().iterator();
        System.out.println(itr.next());
    }
}

You can also try this code with Online Java Compiler

Run Code

How to Fix NoSuchElementException

To fix this exception, we must check beforehand whether we should move ahead or not. For this, we need to pre-check the status of the next element. 

To check whether the next element exists or not, we can employ the below method: 

• hasNext(): it determines whether the next element is present. Either true or false is returned.
   

• Java

Java

import java.util.*;
public class main {
    public static void main(String[] arguments) {
        HashMap<Integer, String> map = new HashMap<Integer, String>();

        Iterator itr = map.keySet().iterator();
        if(itr.hasNext()){
            System.out.println(itr.next());
        }
        else{
            System.out.println("No more elements left");
        }
    }

}

You can also try this code with Online Java Compiler

Run Code

You can Practice by yourself with the help of online java compiler.

Pictorial Explanation

Frequently asked questions

How do you fix the no such element exception?

To fix a NoSuchElementException, ensure proper handling, like checking for existence before accessing elements in collections or using try-catch blocks.

How do I return a no such element exception?

To return a NoSuchElementException, throw it explicitly when encountering scenarios where elements are expected but not found.

What is the use of the Java util package?

It contains the classes needed to make an applet that can communicate with its applet context. It includes all the classes needed to create user interfaces and paint graphics and pictures.

Why do we use import Java util.*?

It means importing all the classes and interfaces within java.util package and making them available within the current class or interface. This is shorthand wild card annotation for importing all classes within a particular package. 

Conclusion 

To wrap up the article, we have extensively discussed java util NoSuchElementException and how to fix it. At last, we have discussed about some faqs based on the same.

Refer to our Guided Path on Coding Ninjas Studio to upskill yourself in Python programming language, Competitive Programming, JavaScript, System Design, and many more! If you want to test your competency in coding, check out the mock test series and participate in the contests hosted on Coding Ninjas Studio! But you have just started your learning process and are looking for questions from tech giants like Amazon, Microsoft, Uber, etc. In that case, you must look at the problems, interview experiences, and interview bundle for placement preparations.

Nevertheless, consider our paid courses to give your career an edge over others!

Check out this article - Balanced Parentheses

Do upvote our blogs if you find them helpful and engaging!

Happy Learning!