[SOLVED] Gradle and Java build jar

Gradle and Java build jar

Does Gradle support backward compatibility for build Java? For example, can Gradle version 8.5 build Java 11 or Java 8 jar files?

Generally, how to choose Gradle to build a Java code for JDK 11?

Solution

Gradle 8.5 and Backward Compatibility for Building Java

The "Compatibility Matrix" (docs.gradle.org/current/userguide/compatibility.html) page within the user guide provides a detailed overview of the tested and officially supported Java versions for various Gradle releases.
This matrix outlines the compatibility for both running the Gradle build process itself and for utilizing Java toolchains to compile and test code against specific JDKs.
While the compatibility matrix offers a solid foundation for understanding supported configurations, it is important to note that Gradle's toolchain support often extends its ability to work with newer Java versions even before they are explicitly listed as fully supported for running Gradle. This proactive approach allows developers to leverage newer Java features with potentially older Gradle versions, although official support guarantees a higher level of stability and testing.
Referring to the compatibility matrix, Gradle 8.5 demonstrates robust compatibility with Java 11. The matrix explicitly states that Gradle 8.5 supports running on Java versions ranging from 8 up to 23.

A key feature enabling Gradle's flexibility in handling different Java versions is the concept of Java toolchains.

Toolchains allow Gradle to utilize a specific JDK for compiling, testing, and running Java code, independent of the Java Virtual Machine (JVM) that Gradle itself is running on.
This decoupling is crucial for projects that need to target a particular Java version while the build environment might have a different Java version configured.
Java toolchains are configured within the build.gradle or build.gradle.kts file using the java.toolchain block. For example, to specify that a project should be built using Java 11, the following configuration can be added:

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(11)
    }
}

Gradle is intelligent enough to automatically detect locally installed JDKs that match the specified requirements. Furthermore, if a suitable JDK is not found locally, Gradle can be configured to automatically download it from configured toolchain download repositories. This feature significantly simplifies the management of JDKs for different projects and ensures that the build process consistently uses the intended JDK, regardless of the underlying environment.