Use Maven to build the api and native artifacts

Not sure this is really relevant for the Rake build but the Java
artifacts should be built with Maven, not JavaExtensionTask. The
latter does not take into consideration Java dependencies and is
difficult to adapt to multiple source directories.

Author: headius

Rakefile

@@ -38,15 +38,8 @@ if RUBY_ENGINE == "ruby" and !ENV["PRISM_FFI_BACKEND"]
     ext.gem_spec = Gem::Specification.load("prism.gemspec")
   end
 elsif RUBY_ENGINE == "jruby"
-  require "rake/javaextensiontask"
-
-  # This compiles java to make sure any templating changes produces valid code.
-  Rake::JavaExtensionTask.new(:compile) do |ext|
-    ext.name = "prism"
-    ext.ext_dir = "java"
-    ext.lib_dir = "tmp"
-    ext.release = "21"
-    ext.gem_spec = Gem::Specification.load("prism.gemspec")
+  task :compile do
+    sh "mvn -f java/pom.xml -pl api -pl native package"
   end
 end