The Java Module System specifies a distribution format for collections of Java code and associated resources. It also specifies a repository for storing these collections, or modules, and identifies how they can be discovered, loaded and checked for integrity. It includes features such as versioning and namespaces with the aim of fixing some of the shortcomings in the existing JAR format, especially the JAR Hell, which can lead to issues such as classpath and class loading problems.
The Java Module System is being developed under the Java Community Process as JSR 277.