How to fix Can’t exceute jar-file:”no main manifest attribute” errors in java? | Projectshop

1. Create a Manifest File (if not already present):

Create a text file named ‘manifest.txt‘ or any name you prefer.

2. Edit the Manifest File:

• Open the manifest file in a text editor.
• Add the following line: ‘Main-Class: your.package.name.YourMainClass‘
• Replace ‘your.package.name.YourMainClass‘ with the fully qualified name of your main class (the one containing the ‘main‘ method).

3. Save the Manifest File:

Save the changes to the manifest file.

4. Create the Jar File with the Manifest:

• Open your command prompt or terminal.
• Navigate to the directory containing your Java files and the manifest file.

5. Execute the Jar Command:

Use the ‘jar‘ command to create the jar file and include the manifest:

jar cfm YourJarFileName.jar manifest.txt *.class

• Replace ‘YourJarFileName.jar‘ with the name you want for your JAR file.
• Replace ‘manifest.txt‘ with the name of your manifest file.
• Replace ‘*.class‘ with the appropriate wildcard to include all your class files.

6. Verify the Manifest in the Jar File:

You can verify that the manifest is included by using the ‘jar‘ command with the ‘tf‘ option:

jar tf YourJarFileName.jar

This command lists the contents of the JAR file. Check if the manifest file is listed.

7. Run the Jar File:

Execute the JAR file using the ‘java‘ command:

java -jar YourJarFileName.jar

Replace ‘YourJarFileName.jar‘ with the name of your JAR file.

Following these steps should fix the “no main manifest attribute” error, allowing you to execute your JAR file successfully. Let me know if you need further clarification!