Java

There are three main features in Java 8 that I love, one of them is the lambda expressions, it will have enormous implications for simplifying development. The another one is the new java.util.stream package provide a Stream API to support functional-style operations on streams of elements. The Stream API is integrated into the Collections API, which enables bulk operations on collections, such as sequential or parallel map-reduce transformations. And lastly but not least the java.time API that now are compatible with lambda, thread safe and simplified usage.

• Java time API
• FizzBuzz
• Hello AWS Lambda
• S3 AWS Lambda
• Configuration with Apache Commons
• Java NIO File Copy
• CSV with Apache Commons
• Read Excel with Apache POI
• Read Filtered Excel with Apache POI
• GMail Mailbox Reader with POP3
• GMail Mailbox Reader with IMAP
• Outlook Mailbox Reader with Exchange
• Streams
• Stream Filters
• Stream Collectors
• Executors
• Generics
• Functional Interfaces
• Lambda Expressions
• Junit 5
• From Anonymous to Lambda
• JFairy Data Generator
• Using Optional
• Builder Desing Pattern
• Mailosaur Getting Started
• GitHub Repository

forEach() in a Map

Iterate over a collection in Java 8 is a really nice one, which lets you pass a method reference or a lambda to receive (key, value) pairs one by one.

import java.util.Map;
import java.util.HashMap;

class ForEachMap {

  void iterate(Map<String, Integer> items){
    items.forEach((k,v) -> System.out.println("Item : " + k + " Count : " + v));
  }

  public static void main(String[] args){
    Map<String, Integer> items = new HashMap<>();
    items.put("A", 10);
    items.put("B", 20);
    items.put("C", 30);

    new ForEachMap().iterate(items);
  }

}

output

Item : A Count : 10
Item : B Count : 20
Item : C Count : 30

forEach() in a List

Also, you can loop a List with forEach

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

class ForEachList {

  void iterate(List<String> items){
    items.forEach(System.out::println);
  }

  public static void main(String[] args){
    List<String> items = new ArrayList<String>();
    items.add("A");
    items.add("B");
    items.add("C");

    new ForEachList().iterate(items);
  }

}

output

A
B
C

NOTE: You can get item from collection like this: items.forEach(item -> System.out.println(item));

You can iterate a Set in the same way

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