Missing (D)TLS IoT oriented features in Java world ?

I'm the main maintainer of [Leshan](https://github.com/eclipse-leshan/leshan) project : a Java LwM2M implementation hosted by Eclipse Foundation.

Until now we are using Scandium (a java DTLS 1.2 implementation hosted Eclipse foundation from Californium project) but recently I need to look at TLS 1.2 for Leshan (because we try to add coaps+tcp support) and I came to the conclusion that :

**There is not so good choice in Java world for DTLS and TLS for IoT**.

I ask myself if my assumption :
- is wrong ? and so I maybe missed something.
- OR is right ? and so we are probably several to face this situation and maybe we can collectively try to improve it.

I created a github repository and begin to summarize some information about that : https://github.com/sbernard31/thermos

The idea would be to :

- Make a good big picture of the situation,
- Collect needs from IoT Java Community,
- Report our need to existing (D)TLS implementation, (to maybe impact their TODO list)
- Find collective solution ?

I try to talk about that at security-dev mailing list from OpenJDK and this is not clear if they will work to improve that situation, here is a link to that discussion : https://mail.openjdk.org/pipermail/security-dev/2024-March/038906.html

After speaking with [Frederic Desbiens](https://accounts.eclipse.org/users/fdesbiens), he advises me to contact Paho project as it could be interested ? If you are, do not hesitate to discuss with us at https://github.com/sbernard31/thermos.

Start by reviewing the thermos repository and the linked OpenJDK security-dev discussion to understand the reported Java DTLS/TLS gaps and Paho's possible needs. Done would require a concrete, agreed scope or integration proposal; the issue currently asks for investigation and community coordination rather than naming a code entry point or test.

Written by the indexing model from the issue text.