HelloWorldJava

A Hello World Java application, which demonstrates project structure and unit tests

Requirements

The application is written for Java 9. Java download: http://www.oracle.com/technetwork/java/javase/downloads/jre9-downloads-3848532.html

$ java --version java 9.0.4 Java(TM) SE Runtime Environment (build 9.0.4+11)

Junit 5 is also required: https://junit.org/junit5/

Basic Configuration

The classpath file (.classpath) contains references to the Java 9 JRE and Junit 5 libraries.

Running the application

The application is mainly meant to be view from within Eclipse (or similar IDE) as a reference. The unit tests can be run to exercise the sample code.

The application can be compiled and run locally:

1. Change to the source file location:

   $ cd /Users/alexburgess/Development/HelloWorldJava/src/main
   

2. Compile the class file:

   $ javac Hello.java
   

3. Execute the file:

   $ cd /Users/alexburgess/Development/HelloWorldJava/src/main
   
   $ java main/Hello
   Hello World!
   

The application can be turned into a jar file for deployment as follows:

1. Change the package location:

   $ cd /Users/alexburgess/Development/HelloWorldJava/src
   

2. Jar up the necessary file, including e flag as there is no manifest file:

   $ jar cfe helloWorld.jar main/Hello main/Hello.class 
   

3. Test the execution:

   $ java -jar helloWorld.jar 
   Hello World!