Merge pull request #32499 from vespa-engine/bjorncs/readme-java-build…

…-mac

Bjorncs/readme java build mac

.java-version

@@ -0,0 +1 @@
+17

README.md

@@ -77,11 +77,44 @@ Some suggested improvements with pointers to code are in [TODO.md](TODO.md).
 ### Development environment
 
 C++ and Java building is supported on AlmaLinux 8.
-The Java source can also be built on any platform having Java 17 and Maven installed.
+The Java source can also be built on any platform having Java 17 and Maven 3.8+ installed.
 Use the following guide to set up a complete development environment using Docker
 for building Vespa, running unit tests and running system tests:
 [Vespa development on AlmaLinux 8](https://github.com/vespa-engine/docker-image-dev#vespa-development-on-almalinux-8).
 
+#### Java environment for Mac
+1. Install [JDK17](https://openjdk.org/projects/jdk/17/), 
+   [Maven Version Manager](https://bitbucket.org/mjensen/mvnvm/src/master/) and [jEnv](https://www.jenv.be)
+   through [Homebrew](https://brew.sh/).
+```sh
+brew install jenv mvnvm openjdk@17
+```
+
+2. For the system Java wrappers to find this JDK, symlink it with
+```sh
+sudo ln -sfn /opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-17.jdk
+```
+
+3. Follow "Configure your shell" in https://www.jenv.be. Configuration is shell specific. For `zsh` use the below commands:
+```sh
+echo 'export PATH="$HOME/.jenv/bin:$PATH"' >> ~/.zshrc
+echo 'eval "$(jenv init -)"' >> ~/.zshrc
+eval "$(jenv init -)"
+jenv enable-plugin export
+exec $SHELL -l
+```
+
+4. Add JDK17 to jEnv
+```sh
+jenv add $(/usr/libexec/java_home -v 17)
+```
+
+5. Verify configuration with Maven by executing below command in the root of the source code.
+   Output should refer to the JDK and Maven version specified in the [.java-version](.java-version) and [mvnvm.properties](mvnvm.properties).
+```sh
+mvn -v
+```
+
 ### Build Java modules
 
     export MAVEN_OPTS="-Xms128m -Xmx1024m"

mvnvm.properties

@@ -0,0 +1 @@
+mvn_version=3.9.9