Java Create JAR Exe Tutorial

updated 22 April 2022

Setting The Windows System Environment

1. Without the compiler added to the Path, you cannot use Java in the Command Prompt.

2. First, install the latest Java SE from:

   https://www.oracle.com/technetwork/java/javase/downloads/index.html

3. After that, in your computer, go to System Properties, you select Advanced System Settings. Or, you can directly search:

   Environment Variables
   

   but, it is better to go to System Properties in Control Panel, because sometimes, coming from search, the computer will not allow you to edit the System Variables.

4. You should now be at Environment Variables window. At the bottom, you will see System Variables, select Path, then click Edit.

5. You should add there the directory of the Java compiler. Copy and paste that at the last part, but be careful! It contains several information that should not be deleted.

   And, when you don't see the last semicolon ; from the last directory, you should add that. Mine is:

   ;C:\Program Files (x86)\Java\jdk1.8.0_144\bin;
   

6. To check whether this is successful, open the Command Prompt and type

   javac
   

   then hit Enter, if the Command Prompt gives you information, then it is successfully added.

Compiling & Running The Java Source Code Through The Command Prompt

1. Change the directory to where you put your source code.

2. But it is better you put your code on the Desktop directory.

3. If the code is on the Desktop, then open CMD, then type

   cd Desktop
   

   then hit Enter, this will bring you to the Desktop.

4. First, you need to compile the Java code in order to run the code.

5. Type javac followed by the filename with the filename extension. Example:

   javac MyFirstProgram.java
   

   then hit Enter.

6. If this is correct, then it will bring you to the next line.

7. Then, type

   java MyFirstProgram
   

   then hit Enter, this will run your code.

8. Now, you have the class file and the java file. It is ready for creating the Executable JAr File.

Creating The Executable JAR File

Remember that Java is a high-level programming language and the creators of this language put some barrier on direct manipulation of the memory for security reasons, unlike C that has a direct access to memory.

Also, one implication is that Java should be portable to any OS. Hence, there is the Java Runtime Environment that contains the Java Virtual Machine to fulfill such a thing.

With that, creating the standard executable file is somewhat different. Hence, they call it as Executable JAr File. JAr stands for Java Archive.

1. Given you are done with the compilation, you need to create the manifest file. Within the same directory create a text document (.txt), name it as manifest.txt so that calling the file will not be hard. Open that and type

   Main-Class: MyFirstProgram
   

   hit Enter twice then save the changes.

   You need to hit Enter twice. Java will fulfill a metadata within the manifest file too.

   Here, I am just using the above example. Of course, if the name of the class file is different, then that should be the name instead of MyFirstProgram.

2. Then after that you are now ready to create the Executable JAr File.

   Open the Command Prompt and change the directory again to where you put your code. Then type

   jar cfm MyFirstProgram.jar manifest.txt MyFirstProgram.class
   

   then hit Enter.

   If you have multiple class files, then include them too. Again, I'm using the above example for continuity. To test whether this is successful, double click the new Executable JAr File, and if the program runs, you're done! Happy coding!

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Useful Links

https://introcs.cs.princeton.edu/java/85application/jar/jar.html

https://www.javatpoint.com/how-to-make-an-executable-jar-file-in-java