Maven Lifecycle and Wrapper

The Default Lifecycle

Maven runs phases in a fixed order. Running a phase runs every phase before it too.

validate -> compile -> test -> package -> verify -> install -> deploy
    |           |         |        |                    |          |
 check pom  javac src  run JUnit  build jar        copy to       upload to a
                                  target/*.jar     ~/.m2 repo    remote repo

Command	What it does
`mvn clean`	delete the `target/` folder
`mvn compile`	compile main code
`mvn test`	compile + run unit tests
`mvn package`	compile + test + build `target/shopease-0.0.1-SNAPSHOT.jar`
`mvn spring-boot:run`	run the app directly (plugin goal, not a phase)
`mvn package -DskipTests`	build without running tests (use carefully)

Phases Run in Order

Example

Simulating Maven: asking for package runs every earlier phase first.

import java.util.List;

public class Main {
    static final List<String> LIFECYCLE =
        List.of("validate", "compile", "test", "package", "verify", "install", "deploy");

    static void mvn(String phase) {
        System.out.println("$ mvn " + phase);
        for (String p : LIFECYCLE) {
            System.out.println("  [INFO] --- " + p + " ---");
            if (p.equals(phase)) break;
        }
        System.out.println("  [INFO] BUILD SUCCESS");
    }

    public static void main(String[] args) {
        mvn("compile");
        mvn("package");
    }
}

Output

$ mvn compile
  [INFO] --- validate ---
  [INFO] --- compile ---
  [INFO] BUILD SUCCESS
$ mvn package
  [INFO] --- validate ---
  [INFO] --- compile ---
  [INFO] --- test ---
  [INFO] --- package ---
  [INFO] BUILD SUCCESS

The Maven Wrapper (mvnw)

Projects from Spring Initializr include mvnw (Linux/Mac), mvnw.cmd (Windows) and a .mvn/ folder. The wrapper downloads the exact Maven version the project needs, so nobody has to install Maven and everyone (including CI servers) uses the same version.

Example

Build the jar with the wrapper (on Windows use mvnw.cmd or .\mvnw):

./mvnw clean package

Example output

[INFO] Scanning for projects...
[INFO] ---------------------< com.shopease:shopease >----------------------
[INFO] Building shopease 0.0.1-SNAPSHOT
[INFO] --- maven-compiler-plugin:3.14.0:compile (default-compile) @ shopease ---
[INFO] --- maven-surefire-plugin:3.5.4:test (default-test) @ shopease ---
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] --- maven-jar-plugin:3.4.2:jar (default-jar) @ shopease ---
[INFO] --- spring-boot-maven-plugin:3.5.6:repackage (repackage) @ shopease ---
[INFO] BUILD SUCCESS
[INFO] Total time:  6.412 s

Tip: Commit mvnw, mvnw.cmd and .mvn/ to Git. Never commit target/ (add it to .gitignore).