javajava-mejarjvm

how to know which class / package/ methods used by given jar file?

I have a jar file. I want to know which external classes and methods are used by classes inside JAR file. Can anyone suggest me any tool?

For example - if below two classes are packaged into Myjar.jar

import java.util.Vector;
class MyJarClass{

    public static void main(String args[]){
        Vector v = new Vector();
        AnotherClass another = new AnotherClass();

        v.addElement("one");
        another.doSomething();

    }
}

class AnotherClass{

    void doSomething(){
    }
}

When I supply that JAR to a tool - the tool should show java.util.Vector and Vector.adElements() are from external source (not present in MyJar.jar)

Forgot to mention, i don't have access to sourcecode.

Solution

  • Easy

    import com.example.*;

    Possible

    List<com.example.MyType> = new ArrayList<com.example.MyType>();

    A challenge

    Class<?> clazz = Class.forName("com.example.MyType");

    Mission impossible

    List<String> classes = getClassNamesFromUrl("http://example.com/classes.txt");
for (String className:classes) {
   doSomethingWith(Class.forName(className));
}

    I support Jon's advice to look at the byte code (BCEL) but just be aware, that in general it is not possible to read all dependencies from a jar, as they can be dynamic and defined outside the library (see: Mission impossible).

    Hard to tell if there's a tool, have a look at those directories on java-source.net:

    Further reading