Add Gradle packaged-JAR conformance example

.github/workflows/ci.yml

@@ -20,3 +20,11 @@ jobs:
           java-version: ${{ matrix.java }}
           cache: maven
       - run: mvn -B test
+      - name: Test Gradle packaged-JAR example
+        if: runner.os != 'Windows'
+        working-directory: examples/gradle-packaged-jar
+        run: ./gradlew --no-daemon test
+      - name: Test Gradle packaged-JAR example on Windows
+        if: runner.os == 'Windows'
+        working-directory: examples/gradle-packaged-jar
+        run: .\gradlew.bat --no-daemon test

README.md

@@ -73,7 +73,8 @@ that is the `package` phase, which runs *after* surefire's `test` phase, so a te
 `target/*.jar` belongs under failsafe (`*IT`, `mvn verify` — and `maven-failsafe-plugin` has to be
 bound in your pom; it is not part of the default lifecycle, and surefire silently skips `*IT`
 classes). With Gradle, make the test task depend on whichever task builds the jar (`jar` or
-`bootJar`). To stay inside the plain `test` run instead: a Spring Boot server can use the `spring:`
+`bootJar`); see the [packaged-JAR Gradle example](examples/gradle-packaged-jar). To stay inside
+the plain `test` run instead: a Spring Boot server can use the `spring:`
 mode below, and any server can be launched straight from the test classpath, no jar needed —
 `command = {"${java.home}/bin/java", "-cp", "${java.class.path}", "com.example.MyServerMain"}`
 (`${...}` expands system properties; this repo's own end-to-end test runs that way).

examples/gradle-packaged-jar/.gitattributes

@@ -0,0 +1,3 @@
+gradlew text eol=lf
+gradlew.bat text eol=crlf
+*.jar binary

examples/gradle-packaged-jar/.gitignore

@@ -0,0 +1,3 @@
+.gradle/
+build/
+!gradle/wrapper/gradle-wrapper.jar

examples/gradle-packaged-jar/README.md

@@ -0,0 +1,42 @@
+# Gradle packaged-JAR example
+
+A tiny Java stdio MCP server and one JUnit conformance test that launches its
+executable JAR. Requires JDK 17+ with `java` on `PATH`; no Gradle or Maven installation
+is needed. The checked-in wrapper downloads Gradle 9.7.1 and verifies its SHA-256
+checksum. Dependencies come from Maven Central, including the released testkit 0.7.0;
+you do not need to build or install the parent project first.
+
+From this directory on Linux/macOS:
+
+```sh
+./gradlew test
+```
+
+On Windows (PowerShell):
+
+```powershell
+.\gradlew.bat test
+```
+
+Use `clean test` to repeat from an empty build directory. The test report is at
+`build/reports/tests/test/index.html`.
+
+The important wiring in [build.gradle](build.gradle) is:
+
+```groovy
+tasks.test {
+    dependsOn tasks.jar
+    useJUnitPlatform()
+}
+```
+
+The `jar` task sets `Main-Class` and bundles Jackson into
+`build/libs/gradle-packaged-jar.jar`. `PackagedJarConformanceTest` uses
+`@McpServerTest(command = {"java", "-jar", "build/libs/gradle-packaged-jar.jar"})`
+to start that artifact over stdio. Gradle runs tests from the project directory,
+so the relative JAR path works on Linux and Windows. Without `dependsOn tasks.jar`,
+`test` compiles the server but does not package it, and a clean run fails to launch it.
+
+For a Spring Boot project, depend on `tasks.bootJar` instead and point the annotation
+at that task's executable JAR. This example uses the plain Java plugin to keep the
+packaging dependency visible.

examples/gradle-packaged-jar/build.gradle

@@ -0,0 +1,38 @@
+plugins {
+    id 'java'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'com.fasterxml.jackson.core:jackson-databind:2.22.2'
+    testImplementation 'io.github.senor14:mcp-java-testkit:0.7.0'
+    testImplementation platform('org.junit:junit-bom:5.14.4')
+    testImplementation 'org.junit.jupiter:junit-jupiter'
+    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+}
+
+tasks.withType(JavaCompile).configureEach {
+    options.release = 17
+    options.encoding = 'UTF-8'
+}
+
+tasks.jar {
+    archiveFileName = 'gradle-packaged-jar.jar'
+    manifest {
+        attributes 'Main-Class': 'example.GreetingServer'
+    }
+    // Include Jackson so the server can run with just java -jar.
+    from { configurations.runtimeClasspath.collect { zipTree(it) } }
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    exclude 'META-INF/*.SF', 'META-INF/*.RSA', 'META-INF/*.DSA', '**/module-info.class'
+    preserveFileTimestamps = false
+    reproducibleFileOrder = true
+}
+
+tasks.test {
+    dependsOn tasks.jar
+    useJUnitPlatform()
+}

examples/gradle-packaged-jar/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,10 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionSha256Sum=acd53f1edaf02f1a8ff99879f8a34b302661a057d9b063ae9e35b552f804d20a
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.7.1-bin.zip
+networkTimeout=10000
+retries=0
+retryBackOffMs=500
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists