How do I reduce the startup time for an uber-jar?

[Sven Auer]

Normally I use the native creation. With this one, the startup times are under one second.  However, since I need Twilio and this does not work as native I am unfortunately dependent on "uber-jar".

The start time is with "uber-jar" more than 5 seconds what is clearly too long.

How can I reduce the startup time of an "uber-jar"?

Thanks for anyone who can help me.

Greetings
Sven

[Sven Auer]

have seen that instead of "uber-jar" there is also "fast-jar". With "fast-jar" it is even a tad faster.
How can I make the start time even faster? If possible.