Add blog post describing Java enhancements

content/posts/0021-java-buildpacks-enhancements.md

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+---
+title: Java Buildpacks enhancements
+date: "2023-06-16"
+slug: java-buildpacks-enhancements
+author: anthonydahanne
+---
+
+During the last few weeks, some enhancements were brought to buildpacks related to the Java ecosystem.
+
+Let's discover what's new!
+
+### TL;DR
+
+Checkout the [samples repository for Java examples](https://github.com/paketo-buildpacks/samples/tree/main/java) and the [Paketo Buildpacks official documentation](https://paketo.io/docs/howto/java/) - those provide way more details about Paketo uses cases (native, certificates, network-less, etc.) than the different build plugins (Maven and Gradle) documentation.
+
+And they're always up-to-date! If the rare event they're not, create an issue or Pull Request, and we will fix that!
+
+## No more Gradle welcome message
+This enhancement was pretty trivial to add, but we hope you will like it: we have disabled Gradle build default welcome message.
+
+It's interesting to learn about Gradle new features in the welcome message, but when you re-build several times with the same gradle version, that does not remember you used it more than once already (because it's run from fresh containers), it can be get a bit repetitive.
+
+More details in the [PR](https://github.com/paketo-buildpacks/gradle/issues/244).
+
+## Additional build arguments for Gradle and Maven
+
+While before you needed to always provide the full arguments lists of arguments even if you just wanted to activate 1 parameter, using 
+* `BP_MAVEN_BUILD_ARGUMENTS` for Maven builds or
+* `BP_GRADLE_BUILD_ARGUMENTS` for Gradle builds
+
+Now you can just append additional arguments to the default BP_{MAVEN|GRADLE}_BUILD_ARGUMENTS, using:
+* `BP_MAVEN_ADDITIONAL_BUILD_ARGUMENTS` for Maven builds or
+* `BP_GRADLE_ADDITIONAL_BUILD_ARGUMENTS` for Gradle builds
+
+More details in the [Maven PR](https://github.com/paketo-buildpacks/maven/pull/265) and in the [Gradle PR](https://github.com/paketo-buildpacks/gradle/pull/238).
+
+## Specify Maven active profiles
+Very similar to the previous enhancement, but just for Maven this time, you can activate a profile without specifying the full list of Maven build arguments now, using:
+
+* `BP_MAVEN_ACTIVE_PROFILES`
+
+This enhancement ([PR](https://github.com/paketo-buildpacks/maven/pull/265)) was actually key for the next item in our list, Spring Boot native detection.
+
+
+## Better Spring Boot Native detection
+
+Since Spring Boot 3.0, Paketo buildpacks support Spring Boot native builds; using a combination of the `bellsoft-liberica`, `spring-boot` and `native-image` buildpacks.
+
+Up until now, it could be tedious for users wanting to get a native build, to specify so many arguments:
+
+```
+pack build applications/native-image \
+  --builder paketobuildpacks/builder-jammy-tiny \
+  --env BP_NATIVE_IMAGE=true \
+  --env BP_MAVEN_BUILD_ARGUMENTS="-Dmaven.test.skip=true --no-transfer-progress package -Pnative" \
+  --env BP_JVM_VERSION=17
+```
+
+Agreed, since the `bellosoft-liberica` buildpack [release 10.0.0 back in March 2023](https://github.com/paketo-buildpacks/bellsoft-liberica/releases/tag/v10.0.0), you no longer need to specify `BP_JVM_VERSION=17` since it's now the default version from 11.
+
+Also, if you've read the previous item, you could argue that you can replace `BP_MAVEN_BUILD_ARGUMENTS="-Dmaven.test.skip=true --no-transfer-progress package -Pnative"` with `BP_MAVEN_ACTIVE_PROFILES="native"`.
+
+Making the previous invocation much simpler:
+
+```
+pack build applications/native-image \
+  --builder paketobuildpacks/builder-jammy-tiny \
+  --env BP_MAVEN_ACTIVE_PROFILES=native \
+```
+
+But that's only improving one use case of Spring Boot native builds (from source code).
+
+If you tried turning a Spring Boot jar built with AOT hints (using `./mvnw package -Pnative` for example), Paketo buildpacks would not know that you wanted a native image from it.
+
+You had to build using:
+
+```
+pack build -p target/spring-boot-demo-0.0.1-SNAPSHOT.jar my-image --env BP_NATIVE_IMAGE=true
+```
+
+which is not super intuitive...
+
+Thanks to [the Spring and Spring boot teams](https://github.com/paketo-buildpacks/spring-boot/issues/273), we found a way to be more clever about native detection: detecting the Spring-Boot-3.1-introduced [`Spring-Boot-Native-Processed` META-INF/MANIFEST entry](https://github.com/spring-projects/spring-boot/issues/35205); turning the previous `pack` invocation into:
+
+```
+pack build -p target/spring-boot-demo-0.0.1-SNAPSHOT.jar my-image
+```