JCache provides a standard caching interface for Java applications which caching vendors implement. At the time of this talk, 4 vendors support the standard with more coming, they are, Oracle Coherence, Hazelcast, Infinispan and EHCache.

1. JCache
(JSR107)
David Brimley
The standard for Java Caching

2. Who is this guy?
Senior Solutions Architect @ Hazelcast
Java Developer for 17 years
@dbrimley
In Memory Data Grids for 8 years
Worked for Investment Banks
Started out coding Basic on a Commodore Vic-20
My fav computer was my old BBC Model B
Long suffering Spurs fan.
HSBC, Nomura, Credit Suisse, BZW, RBoS
Oracle Coherence 4 Years
Pivotal Gemfire 4 Years
David Brimley
Runs HUGL (Hazelcast User Group London)
Low latency trading systems

3. What we’ll cover…
• Why Caching?
• Introduction to JCache.
• Using Caches.
• Entry Processors.
• Listeners.
• Annotations.
• Missing Bits.
• Questions.

4. Who uses caching?
Quick Show of hands

5. Why Caching?

6. Why Caching?
The Speed Factor (Memory .v. Disk)
L1 cache reference 0.5 ns
Branch mispredict 5.0 ns
L2 cache reference 7.0 ns
Mutex lock/unlock 25.00 ns
Main memory reference 100.00 ns
Compress 1k bytes with ZupZ 3,000.00 ns
Send 1k bytes over 1Gpbs network 10,000.00 ns 0.01 ms
Read 4k randomly from SSD 150,000.00 ns 0.15 ms
Read 1 MB sequentially from memory 250,000.00 ns 0.25 ms
Round trip within same datacenter 500,000.00 ns 0.50 ms
Read 1 MB sequentially from SSD 1,000,000.00 ns 1.00 ms
Disk seek 10,000,000.00 ns 10.00 ms
Read 1 MB sequentially from disk 20,000,000.00 ns 20.00 ms
Send packet CA->Netherlands->CA 150,000,000.00 ns 150.00 ms
https://gist.github.com/jboner/2841832

7. Why Caching?
Graph of Memory Prices Decreasing with Time (1957-2014)
http://www.jcmit.com/mem2014.htm
The Cost Factor

8. Why Caching?
Lots of Use Cases
Slow Database
HTTP Proxy
Browser
Persistence Framework
Disk
Application
Hard to scale Database
Lots of Cache Types
Local Cache
Data Grid
Document Store
JPA Second Level
JPA First Level

9. Introduction to
JCache

10. Introduction to JCache
• Caching for the Java Platform
• Produced via the JCP / JSR107
• Ratified March 2014
• 10 years in the making.
• Works with SDK.
• Spec Leads: Greg Luck, Brian Oliver

11. java.util.Map (Java 6/7)
Key-Value Based API
Supports Atomic Updates
Entries Don’t Expire
Entries Aren’t Evicted
Entries Stored On-Heap
Store-By-Reference
https://gist.github.com/jboner/2841832
Introduction to JCache
Map .v. Cache
javax.cache.Cache (Java 6)
Key-Value Based API
Supports Atomic Updates
Entries May Expire
Entries May Be Evicted
Entries Stored Anyware (ie: topologies)
Store-By-Value and Store-By-Reference
Supports Integration (ie: Loaders/Writers)
Supports Observation (ie: Listeners
Entry Processors
Statistics

12. JCache makes NO
assumptions about
topology.
Single Process or
Distributed
Introduction to JCache

13. Introduction to JCache
• JCP Project
http://jcp.org/en/jsr/detail?id=107
• Source Code
https://github.com/jsr107
• Forum
https://groups.google.com/forum/?
fromgroups#!forum/jsr107

14. JSR107 TCK Compliant Vendors
Introduction to JCache
https://jcp.org/aboutJava/communityprocess/implementations/jsr107/index.html
I pity the fool that claims
to support JCache without
TCK compliance
As of 5th March 2015

15. Introduction to JCache
Something to remember when comparing vendors of
distributed caches…
Do NOT Benchmark
with a single
instance!

16. Using Caches

17. Using Caches
<dependency>
<groupId>javax.cache</groupId>
<artifactId>cache-api</artifactId>
<version>1.0.0</version>
</dependency>
Maven Central

18. Using Caches
Classes
Caching
“service loader”
CachingProvider
“SPI Implementation”
CacheManager
“manager of caches”
Cache
“interface to a Cache”

19. Using Caches
Classes
Code Walkthrough

20. Entry Processors

21. Entry Processors
Compute in place
• Atomic Operations in situ of data.
• Eliminate Round-Trips (if distributed)
• Lock Free
• Needs Serialisation (if distributed)
Application Application
Cache Cache

22. Entry Processors
Classes
Code Walkthrough

23. Listeners

24. Listeners
Callbacks for events in Cache
• Follows Observer Pattern
• Interface per event type
• Created, Updated, Removed, Expired
• Iterations of Events passed back
• MutableCacheEntryListenerConfiguration

25. Listeners
Classes
Code Walkthrough

26. Cache Loaders /
Writers

27. Cache Loaders / Writer
Cache Misses / Cache Persist
Application
Cache
Backing Store

28. Cache Loaders / Writer
Classes
Code Walkthrough

29. Annotations

30. Annotations
Spring 4.1, Guice, CDI
• @CacheResult
• @CachePut
• @CacheRemove
• @CacheRemoveAll

31. Annotations
Classes
Code Walkthrough

32. Missing Bits

33. Missing Bits
The Future of JCache
• Async API
• Query
• JEE 8
• Servlet 4.0 (Session Cache)
• Java 8 Lang Features (Lambda/Streams)

34. Questions ?

36. HAZELCAST
• Free London Training
• Hazelcast User Group
• Visit our Booth
Visit our Booth
5th Floor
Get Free Training (Canary Wharf, Thursday 12th March)
http://hazelcast.com/events/
Join the Hazelcast User Group London (HUGL)
http://www.meetup.com/Hazelcast-User-Group-London-HUGL/
Download Hazelcast, the leading open source IMDG
http://www.hazelcast.org

37. THANK YOU.
@dbrimley
david@hazelcast.com