The document discusses building modular Java applications in the cloud, emphasizing agility and modularity as key components for handling change effectively. It highlights the importance of small, disposable components to avoid code rot and improve problem isolation, while recommending OSGi as the current dynamic module framework. Additionally, it outlines deployment strategies, including automated provisioning and scaling of server nodes in a cloud environment.

1. Building Modular
Java Applications
in the Cloud Age
vJUG, March 2015

2. Bert Ertman
Fellow at Luminis (Netherlands)
former JUG Leader for NLJUG
Java Champion
@BertErtman
About me
bert.ertman@luminis.eu

3. Observations
Extremely agile
(first mover advantage)
Architecture (and code base)
should be able to cope with change

4. The case for modularity
Modularity is the
ultimate agile tool!
Small, disposable, components
Prevents code rot on the
architectural level
Isolate problems, focus work

5. Prevent
(tight)
coupling
What we learned about OO design in university :
Promote
cohesion
coupling
cohesion

6. Modules Service Lookups

7. Whatdoweneed
design
consequences
High-level
enterprise APIs
Architectural
focus on
modularity
Runtime
dynamic
module
framework
Right now,
OSGi is the
only option
let’s not
reinvent the
wheel
formodularity?

8. Auth
Blob stores
MongoDB
JPA
Multi-tenancy
OpenSocial
Search
Remote Services
REST
Template
Web
...
Components

9. Stop talking…
and show me code!

10. Products Rest
Products API
Products
Service
MongoDB
Orders Rest
Orders API
Orders Service
MongoDB
Customers API
Customers
Service
MongoDB
... Rest
... API
...
Service
modularity
in action...

11. What about
deployment?

12. Provisioning Server

13. Provisioning servers
Node
AWS Auto Scaling
1. Start
Load Balancer
Apache ACE
2. register
3. register
4. provision
deployment
package

14. Provisioning servers
Nodes are completely disposable
Automated cluster recovery
Nodes do not require maintenance
No “big” container

15. Wrap up

17. Takk
Grazie
Thank
you
Obrigado
Mahalo
Danke
Dank U
Merci
Gracias