Installing Maven on Microsoft Windows

At the time of writing this book, Microsoft Windows 8.1 is the latest version of Microsoft Windows. While the screenshots and output will be for Microsoft Windows 8.1, the steps are similar for earlier (and possibly later) versions as well.

Getting ready

As Maven requires a Java platform, first ensure that you have installed the Java environment on your system, Java Development Kit (JDK) specifically; Java Runtime Environment (JRE) is not sufficient.

You can verify whether Java is installed on your system by opening Add or Remove Programs. If you see something similar to the following screenshot, JDK is installed on your system:

You can also verify the program folder structure from Microsoft Windows Explorer:

How to do it...

Let's start installing Java and Maven by performing the following steps:

1. Set the variable JAVA_HOME to point to the Java installation that you want Maven to use; for example, you can do this by setting JAVA_HOME variable in the following way:

   C:\projects\apache_maven_cookbook>set JAVA_HOME=C:\Program Files\Java\jdk1.8.0_20
   

   Note

   Note that this setting will not be persisted once the command prompt is closed. To persist this, set Environment Variables... using the Control Panel option, as described later for the M2_HOME variable.

2. If JDK is not installed on your system, now is the time to download and install it from the Oracle Java SE download page at http://www.oracle.com/technetwork/java/javase/downloads/index.html.

   Once it is installed, ensure JAVA_HOME is set as described earlier.

   Now that we have set up Java, let us download and set up Maven.

3. Go to http://maven.apache.org/ and click on the Download link.
4. The links to the latest stable versions of Maven are displayed.
5. The binaries are available in both, .zip and .tar.gz formats. Choose one of them.
6. Extract the downloaded binary to a folder you want Maven to reside in. In this case I have chosen C:\software.

   Tip

   It is best to avoid folders with spaces as some features of Maven or its plugins might not work.

7. Ensure the contents are similar to the following screenshot:
   

The preceding screenshot displays a list of directories contained in Maven.

Now let's briefly discuss what these directories contain:

• The bin folder contains the batch files and shell scripts to run Maven on various platforms.
• The boot folder contains the jars required for Maven to start.
• The conf folder contains the default settings.xml file used by Maven.
• The lib folder contains the libraries used by Maven. It also contains an ext folder in which third-party extensions, which can extend or override the default Maven implementation, can be placed.

Now let us make sure we can run Maven from the command prompt by carrying out the following steps:

1. Open Control Panel:
   
2. Choose Advanced system settings:
   
3. Click on Environment Variables.... Add the M2_HOME variable and set it to the folder where Maven was extracted.
   
4. Edit the PATH variable to include Maven's bin folder:
   

How it works...

A Maven installation is essentially a set of JAR files, configuration files, and a Microsoft Windows batch file, mvn.bat.

The mvn command essentially runs this batch file. It first checks for JAVA_HOME. This file is present in the bin folder of the Maven installation and, hence, it needs to be in PATH.

If the batch file does not find JAVA_HOME, it looks for Java in its PATH. This can lead to unexpected results, as typically the Java in PATH is usually the JRE and not the JDK.

The batch file then looks for M2_HOME, which is the location of the Maven installation. It does this so that it can load the libraries that are present.

Additionally, it also reads values specified in MAVEN_OPTS. This variable allows you to run Maven with an additional heap size and other Java parameters.

Using the values for JAVA_HOME, M2_HOME, and Maven_OPTS, the batch file runs its main class org.codehaus.plexus.classworlds.launcher.Launcher.

There's more...

Verify your Maven installation using the following steps:

1. Open a command prompt in Microsoft Windows and run the following command:

   C:\software\apache-maven-cookbook>mvn -version
   

2. The following output should be displayed:

   Apache Maven 3.2.5 (12a6b3acb947671f09b81f49094c53f426d8cea1; 2014-12-14T22:59:23+05:30)
   Maven home: C:\software\apache-maven-3.2.5
   Java version: 1.7.0_67, vendor: Oracle Corporation
   Java home: C:\Program Files\Java\jdk1.7.0_67\jre
   Default locale: en_IN, platform encoding: Cp1252
   OS name: "windows 8.1", version: "6.3", arch: "amd64", family: "windows"
   

See also

• The Creating a simple project with Maven recipe in this chapter