Java requires that big JavaVM to start and during cold starts this together with initializing your code, can take up to twenty seconds. There is also the memory that the JavaVM uses. Both add to the cost of using Java for your lambda. Compare this to a Node, Python or Go lambda and the conclusion would be Java is slow and costs me more.

There are solutions for these problems, but most of them avoid the actual issue (the JavaVM) and are more or less workarounds, like keeping a Lambda warm thus avoiding the cold starts but increasing the number of executions. But I wish to get rid of the JavaVM and that's why ...