For years, we’ve been told that Java suffers from cold starts in AWS Lambda and Serverless in general. Believe it not. Java is extremely fast to start, the simplest Java program starts in milliseconds. It’s the Java app servers, frameworks and libraries that usually slow things down. But there are now many ways to start Java apps fast.

In this session, I want to show you the truth about Serverless Java and cold starts, what’s slow, what’s fast and why it matters. We’ll explore Piranha Cloud, one of the most modern and fastest Jakarta EE frameworks, and how it can start Java apps very fast.

Then I’ll explain which Java Virtual Machine optimizations may help if you need to start apps even faster.

You’ll see live for yourselves how Java AWS Lambda functions built with Jakarta EE can start fast and decrease the cold starts to the absolute minimum which you can barely notice.