As previously mentioned, Project Jigsaw had the goal of modularization. The envisioned standard modular system would be applied to the Java SE platform and the JDK. In addition to efficiency gains, the modular shift would result in better security and ease maintainability. The enhancement detailed in JEP-201 focused on JDK source code reorganization. Let's take a closer look.

Reorganizing the JDK's source code is a significant task and was accomplished with the following subset of goals:

• Provide JDK developers insights and familiarity with the new Java 9 modular system. So, this goal was aimed at developers of the JDK, not mainstream developers. 
• Ensure modular boundaries are established and maintained throughout the JDK build process. 
• The third goal was to ensure future enhancements, specifically with Project Jigsaw, could be easily integrated into the new modular system.

The significance of this source code reorganization cannot be overstated. The pre-Java 9 source code organization was 20 years old. This overdue JDK source code reorganization will make the code much easier to maintain. Let's look at the previous organization of the JDK source code and then examine the changes.