jdep classpath dependency finder

jdep Finds all the files in a given classpath on which some input classes depend. For example:

$ java -jar jdep.jar --classpath jdep.jar:/tmp/classes uk.co.hcsoftware.jdep.Main

 ns.TaskTimer
 uk.co.hcsoftware.jdep.BadClassFileException
 uk.co.hcsoftware.jdep.ClassFinder
 uk.co.hcsoftware.jdep.ClassFinder$ClassFile
 uk.co.hcsoftware.jdep.ClassFinder$FileClassFile
 uk.co.hcsoftware.jdep.ClassFinder$StreamHandler
 ...
  23 dependencies from inputclasses: [uk.co.hcsoftware.jdep.Main]
  (21 classes in classpath)
 250ms to find dependencies
 266ms in total

Prints all classes on which uk.co.hcsoftware.jdep.Main depends.

Notes

Useful if you want to work out what classes/source files you need to ship from a library in order to use some particular class.
Also useful for setting up IDEs (especially ones like IDEA that expect to compile everything under their source root) where not all of the classes under a given root directory are actually reachable from the main class of your project

Limitations

Only finds class-dependencies, not source-dependencies. For example, suppose you have an interface containing statically declared constants. You reference these constants in your .java file and import the interface. javac will inline the values of those variables into your .class file; so whereas your .java file depends on the interface, your .class file does not:
```
     public interface MyConstants{
         public static final int ONE=1;
     }
 
     public class MyClass{
         private int one=MyConstants.ONE;
     }
 
```
MyClass.class does not depend on MyConstants.class (though MyClass.java does depend on MyConstants.java. jdep will not report MyConstants as a dependency of MyClass (this is OK if you're deploying MyClass, but might not be if your trying to determine what source files you need to build MyClass.class).
-warndynamic Running with this option, one tends to get a lot of 'false positives': usages of Class.forName(..) and ClassLoader.loadClass(..) which have been inserted by javac, rather than by the user. It seems that anywhere you put a foo.class variable in your sourcefile, javac loads the class in a static initializer with forName..
Not sure how to eliminate this, but suggest cross-referencing the list with all the .java files that contain these methods..

Usage

$ java -jar jdep.jar

usage: jdep options inputclass1 [inputclass2.. inputclassn] 
 prints out the fully-qualified names of all the classes referenced by the input class(es)
  -c,--classpath <arg> *  classpath value (same syntax as -cp arg to java ;-de
                           limited)
  -i,--ignore <arg>       ignore any classes whose fully-qualified name starts
                           with one of these values (:-separated list)
  -n,--norecurse          just resolve the input classfile, don't attempt to r
                           esolve the classes it references
  -o,--only <arg>         only include classes whose fully-qualified name star
                           ts with one of these values (:-separated list)
  -q,--quiet              just print out resolved classes (or error message if
                           bad invocation) -no extra info
  -s,--sort               sort output classnames lexically
  -w,--warndynamic        look for invocations of Class.forName(..) and ClassL
                           oader.loadClass(..) and warn about them [nothing is 
                           printed in --quiet mode]
 
 * required options

Usage

Examples

List library dependencies 1:

$ java -jar jdep.jar -s -i java -c cglib-nodep-2.1_3.jar;spin.jar spin.CGLibProxyFactory

Find out what I have to ship from cglib if I use the CGLibProxyFactory with spin (the full cglib-nodep-2.1_3.jar is 324k, whereas the classes I need add up to a mere 196k). Sort the output, and ignore anything in the java package

List library dependencies 2:

$ java -jar jdep.jar -sw -i java:javax:org.w3c -c /tmp/classes:/tmp/jars/jdom.jar:/tmp/jars/swing-layout-1.0.jar uk.co.hcsoftware.commander.Main

Find out what I have to ship from from jdom and swing-layout in order not to get NoClassDefFound errors in CommanderBond (turns out almost everything). Warn about dynamic classloading, and ignore files in the java, javax, org.w3c packages

Auto-generate a ClearCase config.spec:

$ jdep -qs -o uk.co.hcsoftware -c /lib/abc.jar uk.co.hcsoftware.commander.Main | grep -v '\$' | sed -e 's/\./\\/g' -e 's/^/load \\fo_hcs\\java\\src\\/g' -e s/$/.java/g >> config.spec

Write a ClearCase-style list of load rules for all the classes I need to fetch into my source view if I am working on the project the mainclass of which is uk.co.hcsoftware.commander.Main (Excludes inner classes, converts classnames to clearcase paths, prepends the load directive, appends .java

Extract some source files from a library:

$ jdep -c jdnc-0_7-all.jar -s org.jdesktop.swing.JXTable | grep -v \$ | sed -e 's/\./\\/g' -e 's/$/.java/g' > sourcefiles

$ Treecopy /tmp/jdnc/src sourcefiles /tmp/to

I want to use JXTable in my project
I don't want everything in jdnc/src, just the files required by JXTable.
Therefore, I want to extract just these .java files into /tmp/to, maintaining the package hierarchy

First I build a list of all the necessary classes, stripping out inner classes and appending '.java' to the classnames.
Next I use the Treecopy .tscape script to copy the listed files from one directory to another, preserving the tree structure.

ChangeLog

Feb 2006 version 0.1