Java Cold Startup on AWS λ
5 min read
fairly easy
TL;DR; λ is the future but Java is useless on it
This is my second newsletter. I am still writing about the things I'm currently obsessed with.


AWS lambda is a serverless platform. Serverless platforms are built on three fundamental ideas:

Program Isolation. Each customer programs is run in a restricted environment in its own container. Stateless. The running program is stateless. If you want to save states, you need to use another service on top of λ such as a database. Pay by execution time. You pay only for the time your program is running. With λ it is billed by slice of 100 ms. I.e. Not running the program is free. Running the program for 10 users is 10x more expensive than for 1.

Why would you use serverless instead of your usual VM? Because those 3 breakthrough ideas have very interesting corollaries.

All *ities disappear. Scalability, reliability and availability become your cloud provider jobs.

Cheaper . Both in terms of ops (no more waking up at 3 am because of a server crash) and actual cost. In the case of Inboxbooster, this reduced our server cost by 3 and removed the nightly crash pain.

Architecture. FaaS (function as a service) contraints a certain architecture (stateless, secure,…). These constraints are really well thoughts and useful. We don't shoot ourselves in our foot anymore.

(source )

Actual serverless user statistics is very opaque (usually a sign that this is growing fast). Nevertheless, I found two interesting sources from Datadog and New Relic. The data below are snippets from their whitepaper. They have been written on their customers running on serverless. Keep in mind thse data are biased towards large companies. They are APM companies with minimal ARR > 5K$. Nimble startups and small companies won't use them.


(source New Relic White Paper)

Serverless growth is impressive. It is…
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