java

In this short Java tutorial, you will learn how to quickly generate a serialVersionUID for a given class. Most Java IDEs provide a support for generating serialVersionUID automatically while some require you to install a plugin for you to generate this value. Generate SerialVersionUID for a Java Class There is a built-in command in JDK…

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Almost in every RESTful Web Service application, I have to do the DTO to Entity and then Entity to DTO conversion. DTO stands for Data Transfer Object and is a simple Plain Old Java Object which contains class properties and getters and settings methods for accessing those properties. In this blog post, I am going…

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With this blog post, I am going to share with you how to quickly create a very simple Spring MVC Web Service project and then build and run it with Maven. In my following blog posts, I am going to enhance this Web Service project and add more functionality to it. And to begin with,…

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Adding dependency injection support into Jersey 2 Web Services application that uses HK2 is not very straightforward. So, I created this page to document things I needed to do in my Jersey 2 RESTful Web Services app to make the Dependency Injection work. Hope you will find it useful. Create a new class that extends AbstractBinder. This…

Read More Dependency Injection with HK2 in Jersey and JAX-RS

Create a Servlet Container deployable Jersey web application Create new Jersey web application using Maven. The project created with the below jersey-quickstart-webapp archetype can be built and deployed to a servlet container like for example Apache Tomcat. mvn archetype:generate -DarchetypeGroupId=org.glassfish.jersey.archetypes \ -DarchetypeArtifactId=jersey-quickstart-webapp -DarchetypeVersion=2.26 POM.XML Dependency to Support JSON To support JSON in your Jersey Web App add…

Read More RESTful Web Services with Jersey and Spring Data JPA – Cheat Sheet

Recently I have published a video course that teaches how to use Java JAX-RS to create a RESTful Web Service for your mobile application and how implement features like user Sign up, Sing in and how to communicate with protected Web Service Endpoints. I would love it if you check it out and hopefully like it, find…

Read More Deploy Web Application Archive(WAR) to Amazon AWS EC2 Linux Instance

In this blog post I would like to share with you how to use Java 8 Functional Interfaces and how to create your own functional interface. What is Functional Interface? Functional interface is a Java interface with single abstract method. Below is a very simple example of a functional interface: package com.appsdeveloperblog; @FunctionalInterface public interface MyFunction<A,…

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In this short Java programming tutorial I am going to share with you how to take a String value and Base64 encode it. We will then take the Base64 encoded String value and will decode it back into original String. There are different libraries out there that allow us to use Base64 encoding and decoding and…

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In this Java programming tutorial I would like to share with you a sample Java code that uses Amazon AWS SES(Simple Email Service) Java SDK to send an email message. I used this code implement Email Verification feature for my mobile app. The code below would send an email message containing an email verification link…

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When you start building a mobile app most likely you will need to build pages like user Sign up and once user has successfully registered, you will need to create a Sign in page. I have created many video tutorial how to implement these pages in Swift and if you follow those you will no doubt…

Read More REST API with Java JAX-RS. Create and Deploy to Amazon Cloud.

With this tutorial I wanted to share with you how to configure your Java project and it’s hibernate configuration file hibernate.cfg.xml to use a more professional and production ready connection pool provider C3P0. Hibernate’s internal connection pooling algorithm is rudimentary, and is provided for development and testing purposes. In my earlier blog posts I used…

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In this Java tutorial I am going to share with you how to create an Anonymous java class and also how to Replace Java Anonymous Class with a shorter lambda expression. Let’s start by creating and interface which we will use in this tutorial. Our anonymous java class will implement a single method defined in this java…

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In this short code example I am going to share with you how to concatenate two ArrayList in Java.  Concatenate ArrayList using addAll() function Let’s say we have these two ArrayList(s): List<String> itemsList1 = new ArrayList(Arrays.asList(“One”, “Two”)); List<String> itemsList2 = new ArrayList(Arrays.asList(“Three”, “Four”)); To concatenate the two lists together we can create a new ArrayList, and…

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When writing a JUnit test there are different ways to test for expected exception and below I am going to share with you three different ways. Using @Test Expected Attribute One way to test for expected exceptions is to use the @Test’s expected attribute to specify that the method below should throw an exception specified by…

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