Jakarta Commons Cookbook

1.1. Obtaining Commons Lang

Problem

You want to use Commons Lang because your program needs to use some of the simple utilities this component provides, such as array manipulation, date manipulation, and enums.

Solution

To download the latest version of Commons Lang, follow these steps:

1. In a web browser, open the URL http://jakarta.apache.org/site/binindex.cgi. This URL will select a mirror, and generate a page with links to download binary distributions from an Apache mirror.

2. Find the Commons Lang project section. If you search for the term “Commons Lang,” you will find a section that provides a link to download the latest binary release of Commons Lang.

3. Click on either the 2.0 zip or 2.0 tar.gz (depending on your platform) to download Commons Lang 2.0.

4. Unzip or untar the binary distribution. This will create a directory named commons-lang-2.0. The commons-lang-2.0 directory should now contain a Java Archive (JAR) file, commons-lang-2.0.jar.

5. Copy or add commons-lang-2.0.jar to your classpath.

Discussion

Step #5 varies based on your development environment. If you are working with Apache Ant as a build tool, you will need to make sure that your classpath includes the Commons Lang JAR. If you are using an Integrated Development Environment (IDE) like Eclipse, you will need to copy this JAR to a directory in your project, and alter your project’s preferences to add Commons Lang 2.0 to the “Java Build Path.” If you are using Maven as a build tool, add the following dependency to the dependencies section of your project.xml:

<dependencies>
  <dependency>
    <id>commons-lang</id>
    <version>2.0</version>
  </dependency>

  ...other dependencies...
</dependencies>

The Commons Lang library includes utilities for working with dates, exceptions, arrays, enums, and more. It is one of the most widely used libraries in open source Java. To learn more about Commons Lang, visit the Jakarta Commons Lang web site at http://jakarta.apache.org/commons/lang/.

Tip

At the time of writing, the most recent version of the Commons Lang component was Version 2.0. If there is a more recent version of Commons Lang available, use the latest version. Although not a guarantee or a promise, most Jakarta Commons components strive for backward compatibility. If an interface has been altered or functionality removed, it will be noted in the release notes for a newer version. If you are going to use a different version of the Commons Lang component with the recipes in this chapter, make sure to read the release notes, which are stored in the file RELEASE-NOTES.txt.

See Also

If you are having an issue with one of the utilities in Commons Lang, see Recipe 1.2 on joining the Commons-user mailing list. If you are looking for the source code, see Recipe 1.3 on obtaining the source code for Commons Lang. You can also visit the Commons Lang web site at http://jakarta.apache.org/commons/lang.