ant ftp task libraries: jakarta-oro; commons-net

A problem

Update: 6 April 2012 This stopped working again. Adding ant-commons-net-1.7.1.jar to ~/.ant/lib resolved the problem.

My installed version of ant (I presume from Developer Tools) doesn't support the ftp task:

$ which ant
/usr/bin/ant
$ ant -version
Apache Ant version 1.7.0 compiled on August 25 2008
$ ant -diagnostics | grep ftp.*Available
ftp : Not Available (the implementation class is not present)
$

The manual says To use the FTP task, you need jakarta-oro 2.0.8 or later, and commons-net

Sounds simple—just find the right .jar files and put them in ~/.ant/lib

jakarta-oro-2.0.8.jar is easy to find.

commons-net-2.0.jar is also easy to find, as is commons-net-ftp-2.0.jar —but they don't work. For example:

$ ls ~/.ant/lib
commons-net-2.0.jar jakarta-oro-2.0.8.jar
$ /usr/bin/ant -diagnostics | grep ftp.*Avail
ftp : Not Available (the implementation class is not present)
$

ant-commons-net-1.7.1.jar does work with Ant version 1.7.0 — and you can find it if you look.

But there is an easier way...

The solution

Update to Ant version 1.7.1 (I did this from MacPorts with Porticus; Fink also has this version):

$ which ant
/opt/local/bin/ant
$ ant -version
Apache Ant version 1.7.1 compiled on June 27 2008
$ant -diagnostics | grep ftp.*Available
$ ls ~/.ant/lib
$

The MacPorts installation includes the requisite java archives. (I haven't tested the Fink install.)

ant javac Xlint:unchecked

You are porting your code to Java 5.0 (aka 1.5); building your project under Xcode gives the following notes from javac:

[javac] Note: Some input files use unchecked or unsafe operations.
[javac] Note: Recompile with -Xlint:unchecked for details.

This raises the following question:
Q: How do I pass -Xlint:unchecked to an ant javac task?
A: Edit the relevant target in your build.xml file to add an embedded compilerarg entry, to the javac task:
<compilerarg value="-Xlint:unchecked"/>
or
<compilerarg value="-Xlint"/>
so it reads something like this:

<target name="compile" description="Compile code">
       <mkdir dir="${bin}"/>
       <mkdir dir="${lib}"/>
       <javac srcdir="${src}" destdir="${bin}" 
              includeAntRuntime="no" 
              classpathref="lib.path" 
              debug="${compile.debug}">
           <compilerarg value="-Xlint"/>
       </javac>
</target>

Using "-Xlint" enables all recommended Xlint options, including :unchecked. See the Sun javac documentation (scroll down to Xlint) for details of other options, giving finer control if you need it.