Maven is neither a part of the operating system nor the JDK. It has to be downloaded and installed in a very similar way to Ant. You can download Maven from its official website (https://maven.apache.org/) under the download section. Currently, the latest stable version is 3.5.4. When you download it, the actual release may be different; instead, use the latest stable version. You can download the source or the precompiled version. The easiest way is to download the binary in tar.gz format.
After the file is downloaded, you can explode it into a subdirectory ...