Extract source code from .jar file

Is there a way to extract the source code from an executable .jar file (Java ME)?

Can you decompile a jar file?

If you're looking for an easy solution, download Windup and run it's command-line version on your . jar. It will decompile using FernFlower, with support up to Java 8 (jad only suports up to Java 1.3, JavaDecompiler up to Java 1.5 IIRC), with a fallback to Procyon if FernFlower fails.

How do I view the source code of a jar file in Eclipse?

Or, if this source jar file contains the sources of a classes jar file that is used as a library in your Eclipse project, just right-click on this jar file, select "Properties", then "Java Source Attachment", then "External File", and select the source jar file.

Use JD GUI. Open the application, drag and drop your JAR file into it.