Maven / Gradle

# ===== Create a project =====
mvn archetype:generate \
  -DgroupId=com.example -DartifactId=myapp \
  -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
cd myapp

# ===== pom.xml structure =====
<project xmlns="http://maven.apache.org/POM/4.0.0">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>myapp</artifactId>
  <version>1.0.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <properties>
    <maven.compiler.release>21</maven.compiler.release>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter</artifactId>
      <version>5.10.2</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>3.2.2</version>
      </plugin>
    </plugins>
  </build>
</project>

# ===== Lifecycle =====
mvn validate           # check pom + project sanity
mvn compile            # compile main sources
mvn test               # compile + run unit tests
mvn package            # compile + test + package (jar/war)
mvn verify             # package + integration tests
mvn install            # verify + install into local repo
mvn deploy             # install + push to remote repo

# Skip tests (use sparingly):
mvn package -DskipTests
mvn package -Dmaven.test.skip=true   # also skips compile

# ===== Common plugins =====
# maven-compiler-plugin   compile sources
# maven-surefire-plugin   unit tests
# maven-failsafe-plugin   integration tests (run during verify)
# maven-shade-plugin      uber-jar with deps included
# spring-boot-maven-plugin Spring Boot fat-jar / native-image
# jacoco-maven-plugin     test coverage
# spotless-maven-plugin   formatter / linter

# ===== Dependency management =====
# Scope:
# - compile (default)   on classpath always
# - provided            available at compile but provided by runtime (servlet API)
# - runtime             not at compile; at runtime (e.g. JDBC driver)
# - test                only for test phases
# - system / import     special

# Exclude transitive:
<dependency>
  <groupId>com.foo</groupId>
  <artifactId>bar</artifactId>
  <version>1.0</version>
  <exclusions>
    <exclusion>
      <groupId>com.baz</groupId>
      <artifactId>old-thing</artifactId>
    </exclusion>
  </exclusions>
</dependency>

# ===== Profiles =====
<profiles>
  <profile>
    <id>prod</id>
    <properties>
      <env>production</env>
    </properties>
  </profile>
</profiles>

mvn package -Pprod

# ===== Multi-module =====
# Parent pom with packaging=pom listing <modules>.
# Child poms inherit + override.

# ===== Useful commands =====
mvn dependency:tree                              # see resolved deps
mvn dependency:analyze                            # find unused / undeclared deps
mvn versions:display-dependency-updates           # check for newer versions
mvn help:effective-pom                            # see inherited + merged pom

# ===== Patterns =====
# - properties for version pinning; single source of truth
# - dependencyManagement block for multi-module version control
# - Spring Boot / Quarkus parents take care of most plugin config
# - Use a build wrapper (mvnw) so teammates use the same Maven version

# ===== Pitfalls =====
# - Skipping tests in CI to ship faster -> regressions
# - SNAPSHOT versions in production -> non-reproducible
# - Multi-module without dependencyManagement -> version drift
# - Manual phase invocation (mvn surefire:test) instead of mvn test

# Maven
mvn clean install
# Gradle
./gradlew build