We've looked at creating complete modular runtime images and learned about the advantages of the linking process, but sometimes that may not be what you want. Suppose you are a library developer and you just want to bundle a single utility module as a jar file. When building a jar file from a module, you have an option of creating a modular JAR file. A modular jar file is just like any other jar file, but with the module-info.class file in the root directory. You can use this to distribute compiled modules as a single file instead of the whole module folder. You can drop a modular JAR file in a module path when running the java command, and it behaves just like the compiled module folders that we've been dealing with.
To illustrate this, let's replace a couple of modules in the out folder of the address book application with modular JAR...
