finding classes in a series of jar files that implement a specific interface

7 Jul 2006 18:43:09 -0700
Hi, I'm trying to solve the following problem but I'm stumped as to how
I can do it 'properly' :(

I have a set of jar files containing classes and I would like to make
a list of names of the classes that implement an interface, say, X.

The code I'm using is given below. The problem is that I get
ClassDefNotFound and UnsatisfiedLinkError exceptions. I can see why
this would happen: a class, C, depends on another class B, which I
don't have in my jar file (or classpath) because I don't need C in the
first place.

However the code has to try and examine each and every class to
determine it's interface.

My question is: is it at all possible to try and load a class with
loading the classes it depends on and still be able to the information
regarding the interfaces implemented? I know that I could subclass
ClassLoader - but I did a naive implementation and for every class it
tried to load I got a ClassNotFoundException.

Any pointers towards a solution would be very appreciated.


    for (int i = 0; i < jars.length; i++) {
      JarFile j;
      try {
    j = new JarFile(jars[i]);
    Enumeration e = j.entries();
    while (e.hasMoreElements()) {
      JarEntry je = (JarEntry) e.nextElement();
      if (je.toString().indexOf(".class") != -1) {
        String className = je.toString().replace('/',
'.').replaceAll(".class", "");
        if (className.indexOf("$") != -1) continue;

        Class klass = null;
        try {
        } catch (ClassNotFoundException cnfe) {
        if (klass == null) continue;

        // check that its not abstract or an interface
        int modifer = klass.getModifiers();
        if (Modifier.isAbstract(modifer) ||
        Modifier.isInterface(modifer)) continue;

        // get the interfaces implemented and see if one matches the one
we're looking for
        Class[] interfaces = klass.getInterfaces();
        for (int k = 0; k < interfaces.length; k++) {
          if (interfaces[k].getName().equals(interfaceName)) {
      } catch (IOException e) {

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