Java Test Applications

A collection of applications used for testing the Java buildpack.

Applications

Spring Boot 4.1 (Java 21) — multi-module build

Name	Description
dist-zip-application	A Spring Boot 4.1 application, deployed as a distZip
ejb-application	A Jakarta EE 10 EJB application
groovy-application	A Spring Boot 4.1 application started with groovy
java-main-application	A Spring Boot 4.1 application started with java -jar
java-task-application	A Spring Boot 4.1 CF task application. Tests Spring Boot Start-Class detection and JBP_CONFIG_JAVA_MAIN class override. Push with instances: 0, run via cf run-task
web-application	A Spring MVC 4.1 application (Servlet 6 / WAR)

Spring Boot 3.5 (Java 17) — standalone projects

Name	Description
java-main-application-boot3	A Spring Boot 3.5 application started with java -jar

Standalone projects have their own build.gradle and Gradle wrapper and are not included in the root multi-module build. Build them from their own directory.

Output Content

⚠️ These applications are for CI/integration testing only. Endpoints such as /spring-env, /environment-variables, and /system-properties can expose sensitive runtime values (credentials, service bindings, system properties). Never deploy to production or shared environments.

All applications support the following REST operations:

URI	Description
GET /	The health of the application
GET /active-profiles	The active Spring profiles (e.g. ["cloud"] when java-cfenv is active)
GET /class-path	The JVM system classpath (boot loader only — see /loaded-jars for full picture)
GET /environment-variables	The environment variables available to the application
GET /input-arguments	The list of JVM input arguments for the application
GET /loaded-jars	All jars loaded by the full classloader chain including BOOT-INF/lib/
POST /out-of-memory	The URL to trigger an out of memory error
GET /request-headers	The http request headers of the current request
GET /security-providers	The system security providers available to the application
GET /spring-env?key=<property>	A single Spring Environment property value (404 if absent)
GET /system-properties	The system properties available to the application

java-main-application-boot3 exposes only GET / (health).

Building

Prerequisites

• JDK 21 for the multi-module build (Spring Boot 4.1 modules)
• JDK 17 for standalone Spring Boot 3.5 projects

Both JDKs can be managed with sdkman:

sdk install java 21.0.10-librca
sdk install java 17.0.19-tem

Note: This applies to the root multi-module build (Gradle 9.6.1 / ASM 9.9, supports Java 21–26). java-main-application-boot3 is a standalone project with its own Gradle wrapper — check its wrapper version separately. Java 27+ requires a newer Gradle release. Java 21 is recommended — it matches the project toolchain. To pin the daemon, add org.gradle.java.home=/path/to/java21 in a local (uncommitted) gradle.properties.

Multi-module build (Spring Boot 4.1)

./gradlew

Standalone projects (Spring Boot 3.5)

cd java-main-application-boot3
./gradlew bootJar

Building Behind a Proxy

Since this project downloads its dependencies from the internet, building behind a proxy requires some extra effort. Configure Gradle with the following system properties (more information here):

./gradlew -Dhttp.proxyHost=<HOST> -Dhttp.proxyPort=<PORT>

Deploying to Cloud Foundry

Each test application contains a manifest.yml file which allows the built application to be deployed to Cloud Foundry by simply issuing:

cf push

To avoid clashing with the URLs of other applications, you should specify your own subdomain for the application (unless the test application does not need a subdomain).

Failure Testing

Failure testing is supported for each of the above applications by setting a suitable environment variable.

If the environment variable FAIL_INIT is set, the application will fail to initialize:

cf set-env <application name> FAIL_INIT true

If the environment variable FAIL_OOM is set, the application will repeatedly exhaust the heap until the JVM is killed:

cf set-env <application name> FAIL_OOM true

Running Tests

To run the tests, do the following:

./gradlew

License

The project is released under version 2.0 of the Apache License.