David R. Heffelfinger

We've all been there at some point or another. We just inherited a big pile of legacy Java code that we need to maintain. This code likely is using some big convoluted ANT script to be built. This being legacy code, it does not use a dependency manager like Ivy or the one included with Maven.

We, of course, want to be able to build using our favorite Java IDE, be it Eclipse, NetBeans or IntelliJ IDEA. Our Java IDE, of course, has no idea of what our project dependencies are, therefore our code is riddled with squiggly red lines due to missing dependencies all over. We are going to manually add dependencies to our project, oh joy. In many cases, these dependencies are scattered across multiple directories, we may have to inspect the contents of most of our JAR files to find many of our dependencies, especially those built in-house.

I was recently in this situation myself, to ease my pain, I came up with a Groovy script that recursively inspects every JAR file in the current directory and every subdirectory. It takes a single parameter, the name of the class to look for (case sensitive), then recursively checks every JAR file in the current directory all subdirectories. It's only requirement is that the "jar" executable be in the PATH, which should be the case for most Java programmers anyway.

Without further ado, here is the script. Enjoy

#!/usr/bin/env groovy

def cDir = new File(".");
def jarContents;
cDir.eachFileRecurse{file ->
  if (file.name =~ /.*\.jar$/)
  {
    jarContents = "jar tvf ${file}".execute().text;
    jarContents.eachLine{line ->
      if (line.contains(args[0])){
        print "*** found in ${file.canonicalPath}:";
        println line;
      }
    }
  }
}

Recently I needed to write a Groovy script to SFTP a file to a server. With a little bit of googling, I came to the conclusion that the easiest way to do that was to use AntBuilder ANT's scp task.

Since this script is going to be used by several people, I wanted to use groovy Grapes to pull the dependency automatically.

Turns out that AntBuilder doesn't see dependencies pulled with the Grab annotation, after a little bit of some more googling I found the solution. Instead of using the @Grab annotation, use the static grab() method of the Grape class to pull the dependencies, this allows us to specify that we need the rootLoader as the class loader, which AntBuilder can see.

Without further ado, here is the script in it's entirety for your copying and pasting pleasure:

#!/usr/bin/env groovy
import groovy.grape.Grape;

Grape.grab(group:"ant", module:"ant-jsch", version:"1.6.5", classLoader:this.class.classLoader.rootLoader)
Grape.grab(group:"com.jcraft", module:"jsch", version:"0.1.42", classLoader:this.class.classLoader.rootLoader)

def ant = new AntBuilder();
def pw;

print "password: ";
//the following line does not work under Cygwin, System.console() returns null
pw = System.console().readPassword();
def pwStr = new String(pw);
ant.scp(trust:'true',file:"/path/to/file.txt",
        todir:"user@host:/home/user",
        password:"${pwStr}",verbose:"true");