What is a Module in Java 9 ? Java Modules are a part of Project Jigsaw . A module is a named, self-describing collection of code and data . Its code is organized as a set of packages containing types, i.e., Java classes and interfaces; its data includes resources and other kinds of static information. What are the Type of Modules in Java 9 ? There are two types of Java Modules Java Standard Modules , they start with string java. Java Non-Standard Modules , they start with string jdk. Creating a Custom Module. We can make the following types of modules Module that is independent of all other modules. Module that requires other modules as dependencies. Module that exports itself for use by other packages. Module that imports some modules and exports some packages for other modules to use. Note When we are exporting the packages in modules, only the publically expoted modules are available to use by other modules.(We will get to this later in the post.) A simple module that does not impo...