Environment

https://maven.apache.org/wrapper/
https://maven.apache.org/guides/mini/guide-using-toolchains.html
https://maven.apache.org/configure.html

build environment:
    Maven version
    JDK used to run Maven
    JDK used to compile project
    Maven default options
    repository settings

mvn wrapper:wrapper
./mvnw -v

commit:
    mvnw
    mvnw.cmd
    .mvn/wrapper/maven-wrapper.properties

use:
    ./mvnw in local dev and CI

-B
-Dstyle.color=always

maven.config:
    project-local default Maven CLI options
    keep it small because every Maven command reads it

-Xmx1g
-Dfile.encoding=UTF-8

jvm.config:
    JVM options for the Maven process itself
    not the application runtime JVM

<!-- ~/.m2/toolchains.xml -->
<toolchains>
  <toolchain>
    <type>jdk</type>
    <provides>
      <version>21</version>
      <vendor>temurin</vendor>
    </provides>
    <configuration>
      <jdkHome>/opt/jdk-21</jdkHome>
    </configuration>
  </toolchain>
</toolchains>

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-toolchains-plugin</artifactId>
  <version>3.2.0</version>
  <executions>
    <execution>
      <goals>
        <goal>toolchain</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <toolchains>
      <jdk>
        <version>21</version>
        <vendor>temurin</vendor>
      </jdk>
    </toolchains>
  </configuration>
</plugin>

toolchains:
    Maven can run on one JDK and compile with another JDK

./mvnw -v
./mvnw help:effective-settings
./mvnw help:effective-pom

./mvnw -B dependency:go-offline
./mvnw -o test

dependency:go-offline:
    prefetch dependencies and plugins for later build

-o:
    offline mode, fails if required artifacts are missing locally

check:
    Maven Wrapper committed
    CI uses ./mvnw
    Java version enforced by enforcer
    compiler release configured
    toolchains used when multiple JDKs exist