Platform.sh is a tool for serious people; And serious people use Java tooling.
Anyway, if you are serious or not.. you can now use Ant and Maven build scripts on Platform.sh this is supported for PHP versions 5.6 and up (and will not be back-ported to earlier versions).
This is great news for people who have their tool-chain based on these environments… and this should allow you to pull basically any Java dependency and use it in your Platform.sh project.
So make sure that in your .platform.app.yaml you specify the PHP version as follows:
To use Ant or Maven simply call them from your build hook. Assuming you have a build.xml file in your root directory you could simply run:
hooks: build: ant
For maven you would have a pom.xml file in a subdirectory you would do something like:
hooks: build: mvn compile