Zip to Jar Conversion & Bug Fix

I need help converting .zip files containing Java source files (.java) into executable .jar files with a main class. Currently, the files are not converting correctly.

Key Requirements:
- Convert .zip to .jar
- Ensure .jar is executable
- Java knowledge is essential
- Debug any conversion errors

Ideal Skills:
- Proficiency in Java
- Experience with .jar file creation
- Problem-solving and debugging skills

Please provide a solution to ensure proper conversion and fix any related bugs.