How to display project version in Java

Sometimes, it’s useful to display the project version in your application. That version can be found in the MANIFEST.MF file. It’s located in every JAR or WAR file in the META-INF folder.

example.war -> META-INF -> MANIFEST.MF

If you open that file, you can see some project information. We need to get the Implementation-Version. Here is an example of a MANIFEST.MF file

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven
Built-By: hudson
Build-Jdk: 1.6.0_27
Hudson-Build-Number: 667
Hudson-Project: example
Hudson-Version: 1.400
Implementation-Version: 2.3.1-SNAPSHOT

To get that version I’ll give you a class ManifestInfo.java. The ‘getVersion’ method gives you that implementation-version. Don’t forget to init the class.

package com.laurenthinoul.webapp;

import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletContext;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.context.ServletContextAware;

public class ManifestInfo implements ServletContextAware {

    private static final String VERSION_ROW = "Implementation-Version";
    private static final String MANIFEST_NAME = "/META-INF/MANIFEST.MF";
    private static final Properties MANIFESTINFO = new Properties();
    private static ServletContext servletContext;
    private static final Logger LOGGER = LoggerFactory.getLogger(ManifestInfo.class);

    private static void setContext(ServletContext servletContext) {
        ManifestInfo.servletContext = servletContext;
    }

    public void init() {
        final String name = MANIFEST_NAME;

        try {
            ManifestInfo.MANIFESTINFO.load(servletContext.getResourceAsStream(name));
        } catch (final IOException e) {
            LOGGER.warn(e.getMessage());
        } catch (final NullPointerException e) {
            LOGGER.warn(e.getMessage());
        }

    }

    public String getVersion() {
        return (String) ManifestInfo.MANIFESTINFO.get(VERSION_ROW);
    }

    @Override
    public void setServletContext(ServletContext servletContext) {
        ManifestInfo.setContext(servletContext);
    }
}

When you use Spring, you need to add the line below:

<bean id="manifestInfo" class="com.laurenthinoul.webapp.ManifestInfo" init-method="init" />

Hope this works for you, enjoy!