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Ondro Mihályi @OmniFishEE
Afraid of Java cold starts in Serverless?
Fear not, Java is super fast!
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Ondro Mihályi @OmniFishEE
Who am I?
Java Champion
Czech JUG lead
(CZJUG)
jug.cz or java.cz
Jakarta EE specifications
committer
Director at
OmniFish
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Ondro Mihályi @OmniFishEE
Extensions
Runtime
Function Request
Extensions
Runtime
INIT INVOKE SHUTDOWN
At cold start Every
invocation
Leads to a
cold start
AWS Lambda Lifecycle
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Ondro Mihályi @OmniFishEE
Extensions
Runtime
Function Request
INIT INVOKE
At cold start Every
invocation
Our code
(Java)
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Ondro Mihályi @OmniFishEE
Extensions
Runtime
Function Request
INIT INVOKE
Every
invocation
Our code
(Java)
We pay only for this
AWS Supported
Runtimes
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Ondro Mihályi @OmniFishEE
Where’s the catch?
● Only specific
language versions are
supported
– Java 11, Java 8
● Java 17 still missing
● Some optimizations
require a custom
runtime
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Ondro Mihályi @OmniFishEE
Extensions
Runtime
Function Request
INIT INVOKE
Our code
(Java)
We pay for
everything
Our
custom
runtime
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Ondro Mihályi @OmniFishEE
https://mikhail.io/serverless/coldstarts/aws/
Cold start times on AWS Lambda
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Ondro Mihályi @OmniFishEE
Java startup time
Plain Java starts fast
In milliseconds, way faster than application servers or
most frameworks
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Ondro Mihályi @OmniFishEE
How fast can Jakarta EE be?
Anything close to plain Java start-up times?
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Ondro Mihályi @OmniFishEE
Quarkus framework
Jakarta EE
MicroProfile
Vert.x
RestEasy
Arc (CDI)
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Ondro Mihályi @OmniFishEE
Overview of Quarkus
AOT code
optimization
at build time
Plugins for
many libraries
Imperative
& reactive
AOT injection
at the core
Compile to
native using
Graal VM
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Ondro Mihályi @OmniFishEE
Piranha Cloud
Introducing Piranha Cloud
Exousia (Authorization)
Eleos (Authentication)
Expressly (EL) Transact (JTA)
WaSP (JSP)
Jersey (REST)
Eclipselink (JPA)
Weld (CDI)
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Ondro Mihályi @OmniFishEE
Architecture of Piranha Cloud
Bare‑bone &
fast Servlet
container
Flat classpath,
easy to embed
Jakarta EE
distributions
Extremely
modular &
extensible
Plain Java,
no magic
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Ondro Mihályi @OmniFishEE
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Ondro Mihályi @OmniFishEE
Further optimizations
More
CPU+RAM
Faster JVM
Disable 2nd tier
compilation
Custom JVM
(JLink)
Native binary
(GraalVM)
● CDS
● CRaC
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Ondro Mihályi @OmniFishEE
Conclusion?
Similar APIs
(Jakarta EE, MicroProfile)
Different approaches
(AOT vs. Optimized
code)
Java is not slow,
frameworks are slow
Piranha and Quarkus
can get you up to speed
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Ondro Mihályi @OmniFishEE
Questions
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Ondro Mihályi @OmniFishEE
OmniFish - Jakarta EE Consulting & Support
Jakarta EE
Consultancy
(migrations, tuning)
Jakarta EE
Application
Development
GlassFish
Server
Support
omnifish.ee
Jakarta EE
Training