Preparing the project
We want to separate the source from the generated files, so our Java source files will be in src folder. All generated files should be under build, and there split into several subdirectories for the individual steps: classes for our compiled files and jar for our own JAR-file.
We have to create only the src directory. (Because I am working on Windows, here is the Windows syntax—translate to your shell):
md src
The following simple Java class just prints a fixed message out to STDOUT, so just write this code into src\oata\HelloWorld.java.
package oata;
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello World");
}
}Now just try to compile and run that:
md build\classes
javac -sourcepath src -d build\classes src\oata\HelloWorld.java
java -cp build\classes oata.HelloWorld
which will result in
Hello World
Creating a jar-file is not very difficult. But creating a startable jar-file needs more steps: create a manifest-file containing the start class, creating the target directory and archiving the files.
echo Main-Class: oata.HelloWorld>myManifest
md build\jar
jar cfm build\jar\HelloWorld.jar myManifest -C build\classes .
java -jar build\jar\HelloWorld.jar
Note: Do not have blanks around the >-sign in the echo Main-Class instruction because it would falsify it!
