• Introduction
• Additional features
• How to install mvnd
  • Install using SDKMAN!
  • Install using Homebrew
  • Install using MacPorts
  • Other installers
  • Set up completion
  • Install manually
• Usage
• mvnd specific options
• Configuration
• Build mvnd from source
  • Prerequisites:
  • Build mvnd
  • Install mvnd

This project aims at providing faster Maven builds using techniques known from Gradle and Takari.

Architecture overview:

• mvnd embeds Maven (so there is no need to install Maven separately).

• The actual builds happen inside a long living background process, a.k.a. daemon.

• One daemon instance can serve multiple consecutive requests from the mvnd client.

• The mvnd client is a native executable built using GraalVM. It starts faster and uses less memory compared to starting a traditional JVM.

• Multiple daemons can be spawned in parallel if there is no idle daemon to serve a build request.

This architecture brings the following advantages:

• The JVM for running the actual builds does not need to get started anew for each build.

• The classloaders holding classes of Maven plugins are cached over multiple builds. The plugin jars are thus read and parsed just once. SNAPSHOT versions of Maven plugins are not cached.

• The native code produced by the Just-In-Time (JIT) compiler inside the JVM is kept too. Compared to stock Maven, less time is spent by the JIT compilation. During the repeated builds the JIT-optimized code is available immediately. This applies not only to the code coming from Maven plugins and Maven Core, but also to all code coming from the JDK itself.

mvnd brings the following features on top of the stock Maven:

• By default, mvnd is building your modules in parallel using multiple CPU cores. The number of utilized cores is given by the formula Math.max(Runtime.getRuntime().availableProcessors() - 1, 1). If your source tree does not support parallel builds, pass -T1 into the command line to make your build serial.

• Improved console output: we believe that the output of a parallel build on stock Maven is hard to follow. Therefore, we implemented a simplified non-rolling view showing the status of each build thread on a separate line. This is what it looks like on a machine with 24 cores:

  

  Once the build is finished, the complete Maven output is forwarded to the console.

mvnd is designed to accept the same command line options like stock mvn (plus some extras - see below), e.g.:

--status lists running daemons

--stop kills all running daemons

mvnd --help prints the complete list of options

Configuration can be provided through the properties file. Mvnd reads the properties file from the following locations:

• the properties path supplied using MVND_PROPERTIES_PATH environment variable or mvnd.propertiesPath system variable

• the local properties path located at [PROJECT_HOME]/.mvn/mvnd.properties

• the user properties path located at: [USER_HOME]/.m2/mvnd.properties

• the system properties path located at: [MVND_HOME]/conf/mvnd.properties

Properties defined in the first files will take precedence over properties specified in a lower ranked file.

A few special properties do not follow the above mechanism:

• mvnd.daemonStorage: this property defines the location where mvnd stores its files (registry and daemon logs). This property can only be defined as a system property on the command line

• mvnd.id: this property is used internally to identify the daemon being created

• mvnd.extClasspath: internal option to specify the maven extension classpath

• mvnd.coreExtensionFilePath: internal option to specify the maven extension configuration file path

For a full list of available properties please see /dist/src/main/distro/conf/mvnd.properties.