To run Java code, you first compile .java source files into bytecode .class files using the JDK:
javac MyClass.java
Then, you package the compiled classes and resources into a JAR file:
jar cf myfile.jar *
If you want to create an executable JAR with a specified main class, you need a MANIFEST.MF file that includes the Main-Class entry, and run:
jar cfm myfile.jar META-INF/MANIFEST.MF *
To view or edit compiled .class or .jar files (such as internal Camunda packages), you can use Java decompiler tools:
| Tool Name | Type | Features |
|---|---|---|
| JD-GUI | GUI | Easy-to-use, syntax highlighting, drag & drop support |
| Quiltflower / Fernflower | CLI | Supports modern Java versions, good readability |
| CFR | CLI | Fine control, supports Java 9+ features |
| Procyon | CLI | Accurate with enums, lambdas, Java 8+ |
Example of using CFR decompiler:
java -jar cfr.jar myfile.jar --outputdir output-folder
JAR files are essentially ZIP archives with a specific directory structure for Java applications.
META-INF/MANIFEST.MF specifying the main class is required.If the ZIP file has the correct structure, simply rename:
project.zip → project.jar
jar Tool:From inside the directory with your files:
jar cf myfile.jar *
To include a manifest (for executable JAR):
jar cfm myfile.jar META-INF/MANIFEST.MF *
Locate the JAR file, for example:
C:\Camunda-bpm-run-7.23.0\internal\webapps\camunda-webapp-webjar-7.23.0
Extract the JAR contents:
jar xf camunda-webapp-webjar-7.23.0.jar
Make your changes (e.g., add a new language file in):
META-INF/resources/webjars/camunda/app/cockpit/locales/
Recreate the JAR file with:
jar cf camunda-webapp-webjar-7.23.0.jar *
Replace the old JAR with the new one and restart Camunda.
Test the new language in Camunda’s web interface, for example:
http://localhost:8080/camunda/app/tasklist/default/?locale=fa