We’ve all been there. You inherit a legacy project with no source code, a critical dependency throws an unexplainable error, or a vendor goes out of business taking their documentation with you.
java -jar procyon-decompiler.jar -o ./output MyClass.class If you use IntelliJ IDEA, you already have a decompiler. Open any .class file inside a JAR dependency. IDEA uses FernFlower under the hood. It’s decent for Java 11 but falls behind CFR for bleeding-edge syntax. Real-World Example: Decompiling a Simple Class Let's say you have this compiled UserService.class : decompile java class file
public class UserService private String apiKey = "secret"; public String greetUser(String name) We’ve all been there