Java8: Iterable: forEach Example

'java.lang.Iterable' interface provides forEach method to perform the given action on each element of the iterable. The default implementation of forEach method looks like below.

As you see the default implementation, for each method traverse through each entry of the iterable and perform given action on it.

Example 1: Print country names from the list using forEach function.

countryNames.forEach((data -> {

         System.out.println(data);

}));

Example 2: Print country names in upper case from the list using forEach function.

countryNames.forEach((data -> {

         System.out.println(data.toUpperCase());

}));

Find the below working example.

Test.java

package com.sample.app;

import java.util.ArrayList;
import java.util.List;

public class Test {

 private static List<String> countryNames = new ArrayList<>();

 private static void loadCountriesMap() {

  countryNames.add("Belgium");
  countryNames.add("Cuba");
  countryNames.add("Georgia");
  countryNames.add("Mongolia");
  countryNames.add("Nepal");
  countryNames.add("Poland");
  countryNames.add("Sweden");
 }

 static {
  loadCountriesMap();
 }

 public static void main(String args[]) {
  /* Print country names */
  System.out.println("Country names in raw form");
  countryNames.forEach((data -> {
   System.out.println(data);
  }));

  /* Print country names in upper case */
  System.out.println("\nCountry names in upper case");
  countryNames.forEach((data -> {
   System.out.println(data.toUpperCase());
  }));
 }
}

Output

Country names in raw form
Belgium
Cuba
Georgia
Mongolia
Nepal
Poland
Sweden

Country names in upper case
BELGIUM
CUBA
GEORGIA
MONGOLIA
NEPAL
POLAND
SWEDEN

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