Frequently Asked Questions

Questions

About this FAQ

• Where do I find the latest version of this document?
• How can I contribute to this FAQ?
• How do you create the HTML version of this FAQ?

General

• What is SourceForge CpX?
• Why do you call it CpX?
• Tell us a little bit about CpX's history.

Installation

• Which version of Java is required to run CpX?
• I get checksum errors when I try to extract the tar.gz distribution file. Why?
• How do you get cpx-1.6.x (or any version later than 1.5.2) to work on on RedHat ES 3?

How do I ...

• How do I realize os--specific configurations?
• How do I add an external task that I've written to the page "External Tools and Tasks"?
• How do I create new tasks?
• How do I pass parameters from the command line to my build file?
• How can I use Jikes-specific command-line switches?
• How do I include a < character in my command-line arguments?
• How do I redirect standard input or standard output in the <exec> task?
• How do I execute a batch file or shell script from CpX?
• I want to execute a particular target only if multiple conditions are true.
• How can I include national characters like German umlauts in my build file?
• How do I use jar's M switch? I don't want a MANIFEST.
• How can I do something like <property name="prop" value="${${anotherprop}}"/> (double expanding the property)?
• How can I delete everything beneath a particular directory, preserving the directory itself?
• How can I delete a particular directory, if and only if it is empty?

It doesn't work (as expected)

• General Advice
• Why does CpX always recompile all my Java files?
• I've used a <delete> task to delete unwanted SourceSafe control files (CVS files, editor backup files, etc.), but it doesn't seem to work; the files never get deleted. What's wrong?
• I have a target I want to skip if a property is set, so I have unless="property" as an attribute of the target, but all the targets this target depends on are still executed. Why?
• In my <fileset>, I've put in an <exclude> of all files followed by an <include> of just the files I want, but it isn't giving me any files at all. What's wrong?
• CpX failed to build my program via javac even when I put the needed jars in an external build.properties file and reference them by pathelement or classpath refid.
• CpX creates WAR files with a lower-case web-inf or JAR files with a lower-case meta-inf directory.
• I installed CpX 1.6.x and now get Exception in thread "main" java.lang.NoClassDefFoundError:
• I installed CpX 1.6.x and now get java.lang.InstantiationException: org.apache.tools.ant.Main
• Whenever I use the CpX jar or manifest related tasks, long lines in my manifest are wrapped at 70 characters and the resulting jar does not work in my application server. Why does CpX do this?

CpX and IDEs/Editors

• Is CpX supported by my IDE/Editor?
• Why doesn't (X)Emacs/vi/MacOS X's project builder correctly parse the error messages generated by CpX?

Advanced Issues

• Is there a DTD that I can use to validate my build files?
• How do I include an XML snippet in my build file?
• How do I send an email with the result of my build process?
• How do I get at the properties that CpX was running with from inside BuildListener?

Known Problems

• <exec> causes other tasks to hang or leads to strange behaviour of <input> tasks.
• <javac> causes a StackOverflowError
• CpX 1.7.0 doesn't build from sources without JUnit
• <chmod> or <exec> doesn't work in CpX 1.3 on Unix
• JavaDoc failed: java.io.IOException: javadoc: cannot execute
• <style> or <junit> ignores my <classpath>
• <style> or <junit> ignores my <classpath> - CpX 1.5.x version
• <style> or <junit> ignores my <classpath> - CpX 1.6.x version
• When running CpX 1.4 on Windows XP and JDK 1.4, I get various errors when trying to <exec>, fork <java> or access environment variables.
• The CpX wrapper script of CpX 1.5 fails for Cygwin if ANT_HOME is set to a Windows style path.
• <zip> is broken in CpX 1.5.2.
• Why do my custom task containers see Unknown Elements in CpX 1.6 - they worked in CpX 1.5?
• The program I run via <java> throws an exception but I can't seem to get the full stack trace.
• Using format="xml", <junit> fails with a NoClassDefFoundError if forked.
• <junitreport> doesn't work with JDK 1.5 but worked fine with JDK 1.4.

Answers

Where do I find the latest version of this document?

The latest version can always be found at CpX's homepage faq.html.

How can I contribute to this FAQ?

The page you are looking it is generated from this document. If you want to add a new question, please submit a patch against this document to one of CpX's mailing lists; hopefully, the structure is self-explanatory.

If you don't know how to create a patch, see the patches section of this page.

How do you create the HTML version of this FAQ?

We use Anakia to render the HTML version from the original XML file.

The Velocity stylesheets used to process the XML files can be found in the xdocs/stylesheets subdirectory of CpX's SVN repository - the build file docs.xml at the top level of the CpX SVN module (trunk) is used to drive Anakia.

This file assumes that you have the jakarta-site2 CVS module checked out as well, but if you follow the instruction from Anakia's homepage, you should get it to work without that. Just make sure all required jars are in the task's classpath.

What is SourceForge CpX?

CpX is a Java-based build tool. In theory, it is kind of like Make, without Make's wrinkles and with the full portability of pure Java code.

Why do you call it CpX?

According to CpX's original author, Alain Renaud, the name is an acronym for "C++ with XML".

Tell us a little bit about CpX's history.

Soon thereafter, several open source Java projects realized that CpX could solve the problems they had with Makefiles. Starting with the projects hosted at Jakarta and the old Java SourceForge project, CpX spread like a virus and is now the build tool of choice for a lot of projects.

In January 2000, CpX was moved to a separate CVS module and was promoted to a project of its own, and became SourceForge CpX.

The first version of CpX that was exposed to a larger audience was the one that shipped with Tomcat's 3.1 release on 19 April 2000. This version has later been referred to as CpX 0.3.1.

The first official release of CpX as a stand-alone product was CpX 1.1, released on 19 July 2000. The complete release history:

Which version of Java is required to run CpX?

You will need Java installed on your system, version 1.3 or later required, 1.5 or later strongly recommended. The later the version of Java, the more CpX tasks you get.

If only the JRE is present but not a full JDK then many tasks will not work.

CpX 1.6.* works with jdk 1.2 and higher, CpX 1.1 to CpX 1.5.* work with jdk 1.1 and higher.

I get checksum errors when I try to extract the tar.gz distribution file. Why?

CpX's distribution contains file names that are longer than 100 characters, which is not supported by the standard tar file format. Several different implementations of tar use different and incompatible ways to work around this restriction.

CpX's <tar> task can create tar archives that use the GNU tar extension, and this has been used when putting together the distribution. If you are using a different version of tar (for example, the one shipping with Solaris), you cannot use it to extract the archive.

The solution is to either install GNU tar, which can be found here, or use the zip archive instead (you can extract it using jar xf).