JDK 9 folder structure has changed compared to Java 8; JDK 9 does not have JRE, it is separately installed into a distinct folder. In JDK 9, we can see a new folder called jmod, which contains all the Java platform modules. Java 9 on wards rt.jar and tool.jar is not available in JDK:
All Java modules, src are available from the ..\jdk-9.0.1\lib\src folder, and each module includes module-info.java. The following is a diagram that shows how JDK looks with all modules:
Every other module implicitly or explicitly depends on the
