I think what you really need is a tool doing concatenate and minify or compress JavaScript and CSS assets. Just like asset-pipeline in the Rails world.
As you mentioned you have two projects one's backend is Nodejs, the other is Java, so I will address this question into this two aspects:
Nodejs side
Just like Antoine said, you can use some building tools like gruntjs(http://www.gruntjs.com/) to write a simple task to concatenate all your js files. Or you can serve the concatenated file from backbend using tools like connect-assets(if you happen use connect web framework), more details please refer this question: Concat and minify JS files in Node.
Java side
wro4j is pretty handy, which provide pretty much everything you need to deal with assets in Java project. You can check out the details usage in their github page. Other than this, Google Closure Compiler is also a good choice.
You can just use whatever tools you like to concatenate/minify/uglify multiple javascript files, but some tools might provide easy integration or other features(like server dynamically in server side). So please check out each tools and decide which one you want to use.
So all in all, Angularjs's assets management has no difference with any other Javascript framworks/files, except the template async loading.(if you write template in separate files, please make sure front end can access that template file directly and also skipping the concatenate process of template files).
Hope it helps, thanks.