How to Fix java.util No Such Element Exception in Java?

Asma Mushtaq

What is the reason for NoSuchElementException

The NoSuchElementException in Java is tossed when one attempts to get to an iterable past its greatest breaking point. This truly intends that, this special case is tossed by different accessor strategies to demonstrate that the component being mentioned doesn’t exist . The following() technique in Java returns the following component in the emphasis or NoSuchElementException assuming the cycle has no more components.

How to address NoSuchElementException?

Similarly as with most programming dialects, the Iterator class incorporates a hasNext() strategy that profits a boolean showing assuming the emphasis has any longer components. On the off chance that hasNext() returns valid, the following() strategy will return the following component in the cycle in any case raise special cases assuming the emphasis has no more components. The answer for this? exemption is to actually take a look at whether the following place of an iterable is filled or void . The accompanying techniques are utilized to actually take a look at the following position:

  • hasNext()
  • hasMoreElements()

An unexcepted, undesirable occasion that upset the ordinary progression of a program is called Exception. More often than not special cases are brought about by our program and these are recoverable. Assume on the off chance that our program necessity is to peruse information from the remote record situating in the U.S.A. At runtime, in the event that a remote document isn’t accessible then we will get RuntimeException saying fileNotFoundException. Assuming fileNotFoundException happens we can give the nearby record to the program to peruse and proceed with the remainder of the program typically.

There are mostly two sorts of exemption in java as follows:

1. Actually taken a look at Exception: The exemption which is checked by the compiler for the smooth execution of the program at runtime is known as a really look at special case. In our program, on the off chance that there is a possibility rising checked special cases, obligatory we should deal with that actually look at exemption (either by attempt catch or tosses watchword) if not we will get the gather time mistake. Instances of checked special cases are ClassNotFoundException, IOException, SQLException, and so forth

2. Unchecked Exception: The exemptions which are not checked by the compiler, whether or not developer dealing with such kind of special case are called an unchecked exemption. Instances of unchecked Exceptions are ArithmeticException, ArrayStoreException, and so forth

Regardless of whether the special case is checked or unchecked each exemption happens at run time provided that there is no possibility of happening any exemption at arrange time.

NoSuchElementException:

It is the kid class of RuntimeException and subsequently it is an unchecked exemption. This exemption is rise consequently by JVM and given by the accessors techniques for Enumeration, Iterator or Tokenizer, for example, next() or nextElement() or nextToken() when we are attempting to get to the substance of an exhibit, assortment, or some other article and assuming these items are vacant or then again in the event that we are attempting to get next component subsequent to arriving at the finish of an item then we will get java.util.NoSuchElementException.

In the beneath model we are attempting to get to a HashMap by utilizing the accessor technique next() of the Iterator class however as the HashMap is unfilled we will be going to get NoSuchElementException.

Example 1:

// Java program to demonstrate the occurence of
// NoSuchElementException
 
// import required packages
import java.io.*;
import java.lang.*;
import java.util.*;
 
// driver class
class Geek {
   
    // main method
    public static void main(String[] args)
    {
        // creating an hashmap object
        HashMap<Integer, Integer> map = new HashMap<>();
       
        // creating an iterator
        Iterator itr = map.keySet().iterator();
       
        // trying to access the element
        itr.next();
    }
}

java.util.NoSuchElementException

Example 2:

// Java program to demonstrate the occurence of
// NoSuchElementException
 
// import required packages
 
import java.io.*;
import java.lang.*;
import java.util.*;
 
// driver class
class Geek {
   
    // main method
    public static void main(String[] args)
    {
        // creating an vector object
        Vector<Integer> v = new Vector<>();
       
        // creating an enumertor
        Enumeration enumerator = v.elements();
       
        // trying to access the element
        enumerator.nextElement();
    }
}

java.util.NoSuchElementException

How to tackle this blunder?

Practically every one of the classes whose accessor strategies give NoSuchElementException contains their separate strategy to check whether or not the item contains more components. So to keep away from this NoSuchElementException we want to consistently call,

  • Iterator.hasNext() or
  • Enumeration.hasMoreElements() or
  • hasMoreToken() technique prior to calling straightaway( ) or nextElement or nextToken() strategy.

The following is the execution of the above assertion:

Example 1:

// Java program to remove the occurence of
// NoSuchElementException by using hasNext()
 
// import required packages
import java.io.*;
import java.lang.*;
import java.util.*;
 
// driver class
class Geek {
   
    // main method
    public static void main(String[] args)
    {
        // creating an hashmap object
        HashMap<Integer, Integer> map = new HashMap<>();
       
        // creating an iterator
        Iterator itr = map.keySet().iterator();
       
        // checking the map object using .hasNext()
        // method if it has elements to access
        // or not before accessing the map using
        // .next() method
        while (itr.hasNext())
            System.out.println(itr.next());
    }
}

Output:

java.util.NoSuchElementException

Example 2:

// Java program to remove the occurence of
// NoSuchElementException by using hasMoreElements()
 
// import required packages
import java.io.*;
import java.lang.*;
import java.util.*;
 
// driver class
class Geek {
   
    // main method
    public static void main(String[] args)
    {
        // creating an vector object
        Vector<Integer> v = new Vector<>();
       
        // creating an enumertor
        Enumeration enumerator = v.elements();
       
        // Checking the vector object using
        // hasMorelements method if it has elements
        // to access or not before accessing the vector
        // using .nextElement() method
        while (enumerator.hasMoreElements())
            System.out.println(enumerator.nextElement());
    }
}

Output:

java.util.NoSuchElementException

Also Read: Returning Multiple values in Java

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