JVM Warmup, Warmup in code ???

Alpit Anand
2 min readMay 22


Photo by Ben McLeod on Unsplash

What is Java JVM warmup?

We all had heard this word sometime or other while dealing with Springboot or reading some article (This is more likely). It is, in a nutshell, a term given to JVM caching all important classes while starting up for faster access. It makes them accessible faster during runtime. Other classes are loaded on a per-request basis. Caching is done automatically once when a server gets its request.

Do we need a manual JVM warmup?

The first request made to a Java web application is often substantially slower than the average response time during the lifetime of the process
Mostly it is required by real low-latency applications. i.e HFT, online gaming . Which really can’t compromise performance at any given time.

How can we do a manual warm-up?

Write a couple to test cases for the critical path of the application and run them a couple of times when the server starts up. This will help cache the code before the server gets an external request.

Do we even need it?

If you are reading it here, probably (read it definitely ) not. Warm-up is rarely required, unless one knows for certain. Otherwise one could be introducing unnecessary code and bugs.

Claps, please. :-), will love the feedback.
One can connect me on alpitanand20@gmail.com.
Or just google
Alpit anand you can find me :-D



Alpit Anand

SDE-II at Paypal. Contact for any queries alpitanand20@gmail.com


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