How to Check Jar File Version

To have access to the version of a jar file, you should have access to the jar file. Precisely, you need to take a look at the jar file's manifest.

In case of the J2EE application

String checkjarFilevesion() {

try {

if(logger.isInfoEnabled())

logger.info("Verifying Jar Version");

String jarFilePath = Thread.currentThread().getContextClassLoader().getResource("../lib/javax.jar").getPath().replaceAll("%20", " ").toString();

JarFile jarfile = new JarFile(jarFilePath);

//Implementation-Version: 3.2.6.SP1

Manifest manifest = jarfile.getManifest();

String version = manifest.getMainAttributes().getValue("Implementation-Version");

return version;

} catch (IOException e) {

// TODO Auto-generated catch block

if(logger.isInfoEnabled())

logger.info("Invalid JAR file path");

}

return null;

}

Absolute Path in J2EE Application

String jarFilePath = Thread.currentThread().getContextClassLoader().getResource("../lib/javax.jar").getPath().replaceAll("%20", " ");