How to declare a variable within lambda expression in Java?

A lambda expression is a function that expects and accepts input parameters and produces output results. It is an instance of a functional interface and also known as a single abstract method interface (SAM interface) like Runnable, Comparator, Callable and etc. We can declare a variable as a final string[] array and able to access that array index within a lambda expression.

Example

import java.util.*;

public class LambdaTest {
   public static void main(String args[]) {
      final String[] country = {null};

      List cities = new ArrayList();
      cities.add("Hyderabad");
      cities.add("Ireland");
      cities.add("Texas");
      cities.add("Cape Town");

      cities.forEach(item -> {      // lambda expression
         if(item.equals("Ireland"))
            country[0] = "UK";      // variable array
      });
      System.out.println(country[0]);
   }
}

Output

UK

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Updated on: 14-Jul-2020

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