The solution you select will most likely depend on the type of system you are building.
If you have a small number of users who will be happy to add a plugin to their browser then an RTSP based approach as you have outlined may work - an example plugin for chrome you could experiment with is
The more usual solution is to convert the RTSP stream into a HTTP stream using a proxy or streaming server - again the scale and size of your system will probably dictate what you want to do here.
A 'Rolls Royce' solution which will allow you address as many users as possible with as good quality as possible (based on the current landscape - video keeps changing...) might be:
- video stream encoded with h.264
- transcoded into multiple Bit rate versions to support ABR
- packaged into fragmented mp4 and streamed with both HLS and MPEG DASH (for maximum device coverage)
ABR essentially allows the client device or player download the video in chunks, e.g 10 second chunks, and select the next chunk from the bit rate most appropriate to the current network conditions.
There is an example using GStreamer, an open source streaming server, and hls streaming in this answer here: https://stackoverflow.com/a/35002374/334402
I do realise your question mentioned TomCat and Java, but if you do want this level of service then I would really hesitate to build it from scratch yourself as there is a lot of specialist detail in a streaming server.