Maven defines a standard set of build phases that define the order in which the build tasks are executed. This sequence of build phases is called the Maven lifecycle.

The Maven lifecycle consists of three main lifecycles:

1. Default: The default lifecycle handles the building and deployment of the project. It consists of the following phases:

• validate: validates the project is correct and all necessary information is available
• compile: compiles the source code of the project
• test: tests the compiled source code using a suitable unit testing framework
• package: packages the compiled code into a distributable format, such as a JAR file
• verify: runs any checks to verify the package is valid and meets quality criteria
• install: installs the package into the local repository for use as a dependency in other projects locally
• deploy: copies the final package to the remote repository for sharing with other developers and projects

2. Clean: The clean lifecycle handles project cleaning. It consists of the following phases:

• pre-clean: executes processes necessary prior to the actual project cleaning
• clean: removes all files generated by the previous build
• post-clean: executes processes necessary to finalize the project cleaning

3. Site: The site lifecycle handles the creation of project documentation. It consists of the following phases:

• pre-site: executes processes necessary prior to the actual project site generation
• site: generates the project's site documentation
• post-site: executes processes necessary to finalize the project site generation, and to deploy the site to the server
• site-deploy: deploys the generated site documentation to the specified server

Each lifecycle is made up of a sequence of plugin goals, which perform specific tasks during the build process. When a phase is executed, all of the goals bound to that phase are executed in the order in which they are defined in the POM file.

Understanding the Maven lifecycle is important for creating and configuring Maven projects, as well as troubleshooting build issues.