how to find the jar file containing a class definition?

Question

What is your favorite tool, plugin, script, to find a java class in a bunch of jar files?

Very often I inherit code that complains about a class that doesn't exist, and it is just because the jar file is not included in the classpath. But, in what jar file is the class?

I obviously would prefer an eclipse plugin, but I'm open to any piece of software that works with Windows.

I know... Windows is not my choice, but that's what I got to work with.

Thanks!

Answer 1

I usually employ bash for that: grep -lr "ClassName" . The trick is that names aren't encoded in any way. You can open jar file in text editor and you'll see them. (You can even include package name in search query.)

I suspect, there's some windows equivalent too.

Answer 2

You could always add the Reference library to your project in Eclipse and then in Package Browser, just expand the packages in the JAR file until you find the class that you are looking for.

Answer 3

@Nikita Rybak: AstroGrep for Windows is our friend: http://astrogrep.sourceforge.net/

Answer 4

Very often I inherit code that complains about a class that doesn't exist, and it is just because the jar file is not included in the classpath.

If it's not in the classpath, then you likely don't have the JAR file itself at all. Searching via Eclipse's builtin Ctrl+Shift+T function won't help much. Usually you can make use of the package name to "guess" where you could get the JAR file from at the internet. E.g. a org.apache.commons.lang.XXX class is available at http://commons.apache.org/lang.

For the unobvious ones, I myself use http://www.jarhoo.com, the JAR search engine (which is unfortunately unavailable at that moment!).

Answer 5

use this:

public class Main {

    private static final String SEARCH_PATH = "C:\\workspace\\RPLaunch";
    private static String CLASS_FILE_TO_FIND =
            "javax.ejb.SessionBean";
    private static List<String> foundIn = new LinkedList<String>();

    /**
     * @param args the first argument is the path of the file to search in. The second may be the
     *        class file to find.
     */
    public static void main(String[] args) {
        File start;
        new Scanner(args[0]);
        if (args.length > 0) {
            start = new File(args[0]);
            if (args.length > 1) {
                CLASS_FILE_TO_FIND = args[1];
            }
        } else {
            start = new File(SEARCH_PATH);
        }
        if (!CLASS_FILE_TO_FIND.endsWith(".class")) {
            CLASS_FILE_TO_FIND = CLASS_FILE_TO_FIND.replace('.', '/') + ".class";
        }
        search(start);
        System.out.println("------RESULTS------");
        for (String s : foundIn) {
            System.out.println(s);
        }
    }

    private static void search(File start) {
        try {
            final FileFilter filter = new FileFilter() {
                public boolean accept(File pathname) {
                    return pathname.getName().endsWith(".jar") || pathname.isDirectory();
                }
            };
            for (File f : start.listFiles(filter)) {
                if (f.isDirectory()) {
                    search(f);
                } else {
                    searchJar(f);
                }
            }
        } catch (Exception e) {
            System.err.println("Error at: " + start.getPath() + " " + e.getMessage());
        }
    }

    private static void searchJar(File f) {
        try {
            System.out.println("Searching: " + f.getPath());
            JarFile jar = new JarFile(f);
            ZipEntry e = jar.getEntry(CLASS_FILE_TO_FIND);
            if (e == null) {
                e = jar.getJarEntry(CLASS_FILE_TO_FIND);
            }
            if (e != null) {
                foundIn.add(f.getPath());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 6

In the same lines as BalusC's answer (I can't post comment yet nor link 2 urls, no reputation :( ), you can find a jar thanks to these 2 jar finder engines: - http://www.jarfinder.com/ - findjar