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How to View MANIFEST.MF in a JAR File

MANIFEST.MF is one of the most important metadata files inside a JAR archive. It can tell you how the JAR was built and which class is used as the entry point.

Where is MANIFEST.MF located?

Inside most JAR files, the manifest is stored at META-INF/MANIFEST.MF. You can open a JAR file with this website or the Android app and browse to the META-INF folder.

Important manifest fields

Common fields include Manifest-Version, Main-Class, Created-By, Class-Path, Implementation-Title, and Implementation-Version. Not all JAR files include every field.

Why Main-Class matters

Runnable JAR files usually need a Main-Class entry. If a JAR file does not include Main-Class, Java may not know which class to launch when using java -jar.

View manifest online

Use the upload tool on the homepage, choose your JAR file, then click View MANIFEST.MF. The file is processed locally in your browser.

Try Jar File Opener Online

Use the homepage tool to inspect a JAR file locally in your browser, or download the Android app for offline file inspection on your phone.

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