$show=/label

Java 8 Examples Programs Before and After Lambda & Streams

SHARE:

Quick guide to few example programs on before and after Java 8. Java 8 Concepts further simplifies the code and profound for core logic rather than syntax.

1. Introduction


In this tutorial, We'll learn how to write programs using java 8 coding standards on few examples. Many developers feel learning java 8 concepts may be hard to understand. But once we are good using them then feel reduces error prone code and improves the performance of the application.

Read article on Java 8 Lamda Expression Rules

Examples Programs Before and After Java 8

In this article, We will see the example programs on sorting using Comparator, File names validation, Retrieving only hidden files and filtering list objects based on conditions.

2. Sorting

2.1 Before Java 8


See the below code which is implemented in older versions of Java. Here trying to sort the Employee's based on the id column.

Collections.sort(emplyeesList, new Comparator() {
 public int compare(Employee a1, Employee a2){
  return a1.getId().compareTo(a2.getId());
 }
});


Here, written code in 5 lines in which includes Comparator implementation.

2.2 In Java 8

See the below code in Java 8. All the code is in single line and not seeing comparing logic.

emplyeesList.sort(Comparator.comparing(Employee::getId));

Here, Comparator is a Functional Interface which has only one abstract method.

Comparator has a static method comparing(.Function.) which accepts only Funtion interface.
https://docs.oracle.com/javase/8/docs/api/java/util/function/Function.html

Note: Function<T, R> also a Functional Interface. This has a method apply(T t) which will be called from Comparator.comparing() method.

3. File Name Validation

3.1 Before Java 8


See the code in java old version. Here the core logic is file.getName().endsWith(".xml"); The remaining code is just syntax.

File[] hiddenFiles = new File("directory_name").listFiles(new FileFilter() {
 public boolean accept(File file) {
  return file.getName().endsWith(".xml");
 }
});

3.2 In Java 8

The above code is simplified to single line which reduces the errors.

File[] hiddenFiles = new File("directory_name").listFiles( file -> file.getName().endsWith(".xml"));

Note: Java 8, just focus on the business logic and takes its syntax internally. Developer need not to worry about it.


4. Retrieving only Hidden files

4.1 Before java 8


File has a method to check the method is hidden or not using isHidden() method.

File[] hiddenFiles = new File("directory_name").listFiles(new FileFilter() {
 public boolean accept(File file) {
  return file.isHidden();
 }
});

4.2 In Java 8

Just using the new Method Reference concept as part of new Java 8.

File[] hiddenFiles = new File("directory_name").listFiles(File::isHidden);


5. Conclusion


In this post, We've seen example program before and after Java 8.

Observed the differences between them. Java 8 were in many ways more profound than any other changes to Java in its history.

COMMENTS

BLOGGER

About Us

Author: Venkatesh - I love to learn and share the technical stuff.
Name

accumulo,1,ActiveMQ,2,Adsense,1,API,37,ArrayList,16,Arrays,16,Bean Creation,3,Bean Scopes,1,BiConsumer,1,Blogger Tips,1,Books,1,C Programming,1,Collection,5,Collections,23,Collector,1,Command Line,1,Compile Errors,1,Configurations,7,Constants,1,Control Statements,8,Conversions,6,Core Java,84,Corona India,1,Create,2,CSS,1,Date,3,Date Time API,13,Dictionary,1,Difference,1,Download,1,Eclipse,2,Efficiently,1,Error,1,Errors,1,Exception,1,Exceptions,3,Fast,1,Files,10,Float,1,Font,1,Form,1,Freshers,1,Function,3,Functional Interface,2,Garbage Collector,1,Generics,4,Git,4,Grant,1,Grep,1,HashMap,1,HomeBrew,2,HTML,2,HttpClient,2,Immutable,1,Installation,1,Interview Questions,5,Iterate,2,Jackson API,3,Java,30,Java 10,1,Java 11,5,Java 12,5,Java 13,2,Java 14,2,Java 8,78,Java 8 Difference,2,Java 8 Stream Conversions,2,java 8 Stream Examples,3,Java 9,1,Java Conversions,11,Java Design Patterns,1,Java Files,1,Java Program,3,Java Programs,93,java.lang,5,java.util. function,1,jQuery,1,Kotlin,10,Kotlin Conversions,3,Kotlin Programs,6,Lambda,1,lang,29,Leap Year,1,live updates,1,Logging,1,Mac OS,2,Math,1,Matrix,5,Maven,1,Method References,1,Mockito,1,MongoDB,3,New Features,1,Operations,1,Optional,6,Oracle,5,Oracle 18C,1,Partition,1,Patterns,1,Programs,1,Property,1,Python,2,Quarkus,1,Read,1,Real Time,1,Recursion,2,Remove,2,Rest API,1,Schedules,1,Serialization,1,Servlet,2,Sort,1,Sorting Techniques,8,Spring,2,Spring Boot,23,Spring Email,1,Spring MVC,1,Streams,23,String,58,String Programs,12,String Revese,1,Swing,1,System,1,Tags,1,Threads,10,Tomcat,1,Tomcat 8,1,Troubleshoot,16,Unix,2,Updates,3,util,5,While Loop,1,
ltr
item
JavaProgramTo.com: Java 8 Examples Programs Before and After Lambda & Streams
Java 8 Examples Programs Before and After Lambda & Streams
Quick guide to few example programs on before and after Java 8. Java 8 Concepts further simplifies the code and profound for core logic rather than syntax.
https://1.bp.blogspot.com/-3xS7CCU6oPM/XQc4-vRzUlI/AAAAAAAABqw/Ct-NAUq24pIENu2vc918QAU5JlZQVfyXQCLcBGAs/s320/Examples%2BPrograms%2BBefore%2Band%2BAfter%2BJava%2B8.PNG
https://1.bp.blogspot.com/-3xS7CCU6oPM/XQc4-vRzUlI/AAAAAAAABqw/Ct-NAUq24pIENu2vc918QAU5JlZQVfyXQCLcBGAs/s72-c/Examples%2BPrograms%2BBefore%2Band%2BAfter%2BJava%2B8.PNG
JavaProgramTo.com
https://www.javaprogramto.com/2019/06/java-8-examples-programs-before-and-after-lambda.html
https://www.javaprogramto.com/
https://www.javaprogramto.com/
https://www.javaprogramto.com/2019/06/java-8-examples-programs-before-and-after-lambda.html
true
3124782013468838591
UTF-8
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS PREMIUM CONTENT IS LOCKED STEP 1: Share to a social network STEP 2: Click the link on your social network Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy Table of Content