Can you tell on runtime if you're running java from within a jar?

Question

I have an application that some of my users run from Eclipse, and others run it by using a jar file.

I want some actions to be done when running from within the jar,

Answer 1

If you query the JAR file name it will work if running from a JAR file otherwise it will return something like classes so the following code can be used:

import java.io.File;

public class JarUtilities
{
    public static String getJarName()
    {
        return new File(JarUtilities.class.getProtectionDomain()
                                .getCodeSource()
                                .getLocation()
                                .getPath())
                       .getName();
    }

    public static boolean runningFromJar()
    {
        return getJarName().contains(".jar");
    }
}

EDIT:

If you need more accuracy and to be resistant against renaming of the file extension, checking whether the file contains the MANIFEST.MF should work:

public static boolean runningFromJAR()
{
    try
    {
        String jarFilePath = new File(JarUtilities.class.getProtectionDomain()
                .getCodeSource()
                .getLocation()
                .getPath()).
                toString();
        jarFilePath = URLDecoder.decode(jarFilePath, "UTF-8");

        try (ZipFile zipFile = new ZipFile(jarFilePath))
        {
            ZipEntry zipEntry = zipFile.getEntry("META-INF/MANIFEST.MF");

            return zipEntry != null;
        }
    } catch (Exception exception)
    {
        return false;
    }
}