Declaration

To declare a module, you need to create a file named module-info.java and put it at the top of the folder where your code is.

src/
  example/
    Example.java
  some/
    packageName/
      AClass.java
  module-info.java

Within this file you put module followed by a name for the grouping of packages and {}.¹

module example {
}

Just like with package names, module names can have multiple parts separated by .s.

module a.longer.name {
}

Nothing in this declaration says explicitly what packages are part of the module; it is just assumed that it holds the packages it is "next to."

This name doesn't need to be related to the names of the packages, but whenever possible it's best to pick something that makes sense ↩

Modern Java