1. Project Topic 2: Migration to Java 9
Software Architecture
Fall 2017
Project Mentor: Negar Ghorbani

2. Intro to Java 9 Main Goals The Modular JDK Modular Source Code
Strong Encapsulation - Hide Internal APIs
Improved Accessibility
Being Aware of dependencies
Reliable Configuration
Scale Java SE to smaller devices
Easier to construct and maintain libraries and applications

3. Java 9 Module
A named, self-describing collection of code, data, and some resources
A set of related packages designed for reuse
Java 9 Module
Code
Data + Resources
Module Descriptor
module-info.java

4. Java 8 Vs. Java 9 Application
Module
Module Descriptor
Packages
Packages
Types (Classes, Abstract Classes, Interfaces, …)
Types (Classes, Abstract Classes, Interfaces, …)
Code
Data
Resources
XML
Properties
etc.
Code
Data
Resources
XML
Properties
etc.

5. Module Types Application (Named) Automatic Unnamed Platform
What we are going to create
Third party dependencies
Automatic
For migrating applications and using pre-Java 9 libraries
Any JAR file without module descriptor
Unnamed
Exports all packages and read all modules
Can’t be read, but can read all
Platform
The JDK itself
All the basic Java features

6. Creating a Module What other modules does it depend on?
Depends on java.base by default
Keyword: requires
Requires transitive:
make a module available to other modules as a transitive dependency
What packages it export to other modules?
Can be accessible by other modules (or an specific module)
Nothing exported by default
Sub-packages will remain concealed
Keyword: exports

7. Creating a Module: Example
Dependency Graph
com.seal.utils
example.tools
example.conv

8. Creating a Module: Example
com.seal.utils can only access example.tools package, not any of its sub-packages e.g. services

9. Migration to Java 9 Steps: Running the program
Updating third-party libraries
Compiling the application
Running jDeps tool on the code
An static analysis tool for finding compile dependencies on JDK internal APIs
Resolving the possible challenges

10. Migration to Java 9 Most Common Challenges:
Illegal access to internal APIs
Dependencies on Java EE modules
Split Packages
More info:

11. Class Project Choose a Java software system Choose a team
At least 10K LOC
At least 30 classes
Not developed by you: was developed by others and is used by thousands of people. Publicly available, open source.
Must be unique in class: each group has their own program — no two groups may share the same system.
Must be recognizable, well-used, popular project
Choose a team
Up to three students

12. Class Project: Implementation
Migrate the system to Java 9
Fix the possible problems
Explain the problem, and how you fixed it
Compile and run the system with JDK 9
Define appropriate modules, according to the system’s architecture
Explain the modules and the reason you defined them
Show all the packages and types within each of the modules
Compile and run the system with the modified architecture

13. Class Project: Analysis
Write a report of each task performed, and
Compare the system before and after your architectural modification
Visualize/model the architecture of the system before and after the migration
Explain the difference in any possible aspect
Performance
Encapsulation
Reusability
Maintenance
Security and Accessibility
...
Describe in detail, the resulting advantages of the modified system after migrating to Java 9