feat(core22): maven plugin (#4657)

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

docs/conf.py

@@ -191,6 +191,7 @@
         "common/craft-parts/reference/step_execution_environment.rst",
         "common/craft-parts/reference/step_output_directories.rst",
         "common/craft-parts/reference/plugins/python_plugin.rst",
+        "common/craft-parts/reference/plugins/maven_plugin.rst",
         # Extra non-craft-parts exclusions can be added after this comment
     )
 )

docs/reference/plugins.rst

@@ -11,6 +11,6 @@ Snapcraft.
    :maxdepth: 1
 
    /common/craft-parts/reference/plugins/dump_plugin
-   /common/craft-parts/reference/plugins/maven_plugin
+   plugins/maven_plugin
    plugins/python_plugin
    /common/craft-parts/reference/plugins/rust_plugin

docs/reference/plugins/maven_plugin.rst

@@ -0,0 +1,37 @@
+
+.. include:: /common/craft-parts/reference/plugins/maven_plugin.rst
+   :end-before: .. _maven-details-begin:
+
+Dependencies
+------------
+
+The plugin expects Maven to be available on the system as the ``mvn``
+executable, unless a part named ``maven-deps`` is defined. In this
+case, the plugin will assume that this part will stage the ``mvn``
+executable to be used in the build step.
+
+Note that the Maven plugin does not make a Java runtime available in
+the target environment. In Snapcraft, the developer must stage the
+appropriate packages in order to be able to execute the application
+(unless the Java runtime is provided by a
+content snap).
+
+
+Example
+-------
+
+This is an example of a Snapcraft part using the Maven plugin. Note
+that the Maven and Java Runtime packages are listed as build packages,
+and the Java Runtime is staged to be part of the final payload::
+
+  mkpass:
+    plugin: maven
+    source: .
+    build-packages:
+      - openjdk-11-jre-headless
+      - maven
+    stage-packages:
+      - openjdk-11-jre-headless
+
+.. include:: /common/craft-parts/reference/plugins/maven_plugin.rst
+   :start-after: .. _maven-details-end:

tests/spread/plugins/craft-parts/build-and-run-hello/maven-hello/pom.xml

@@ -0,0 +1,41 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.example</groupId>
+    <artifactId>hello</artifactId>
+    <version>1.0</version>
+
+    <name>hello</name>
+    <description>A test project</description>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.release>11</maven.compiler.release>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.1.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <addClasspath>true</addClasspath>
+                            <classpathPrefix>lib/</classpathPrefix>
+                            <mainClass>com.example.hello.Main</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.10.1</version>
+                <configuration>
+                    <release>${maven.compiler.release}</release>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

tests/spread/plugins/craft-parts/build-and-run-hello/maven-hello/snap/snapcraft.yaml

@@ -0,0 +1,30 @@
+name: maven-hello
+version: '1.0'
+summary: A test project
+description: |
+  A test project for the maven plugin. It says hello.
+
+grade: stable # must be 'stable' to release into candidate/stable channels
+confinement: strict  # use 'strict' once you have the right plugs and slots
+base: core22
+
+lint:
+  ignore:
+    - library:
+        - usr/lib/jvm/java-*/lib/*.so
+
+apps:
+  maven-hello:
+    command: bin/java -jar $SNAP/jar/hello-1.0.jar
+
+parts:
+  hello:
+    plugin: maven
+    source: .
+    build-packages:
+      - openjdk-11-jre-headless
+      - maven
+    stage-packages:
+      - openjdk-11-jre-headless
+    prime:
+      - -usr/lib/jvm/java-11-openjdk-*/lib/security/blacklisted.certs

tests/spread/plugins/craft-parts/build-and-run-hello/maven-hello/src/main/java/com/example/hello/Main.java

@@ -0,0 +1,8 @@
+package com.example.hello;
+
+
+public class Main {
+	public static void main(String[] args) {
+		System.out.println("hello world");
+	}
+}

tests/spread/plugins/craft-parts/build-and-run-hello/task.yaml

@@ -9,6 +9,7 @@ environment:
   SNAP/flutter: flutter-hello
   SNAP/python: python-hello
   SNAP/qmake: qmake-hello
+  SNAP/maven: maven-hello
 
 prepare: |
   #shellcheck source=tests/spread/tools/snapcraft-yaml.sh
@@ -87,6 +88,8 @@ execute: |
     modified_file=lib/main.dart
   elif [ -f src/hello/__init__.py ]; then
     modified_file=src/hello/__init__.py
+  elif [ -f src/main/java/com/example/hello/Main.java ]; then
+    modified_file=src/main/java/com/example/hello/Main.java
   else
     FATAL "Cannot setup ${SNAP} for rebuilding"
   fi