One of the main problem of old and low end java mobile phones is that they do not support RTSP.
But i have founded a browser through which you can watch videos from any website. The browser is Bolt Browser. Bolt is amazing browser from bitestrem with great features like:

1-Full HTML5 support
2-Built in flash player
3-Super fast speed
4-Small size
5-Easy to use
6-Preloaded bookmarks
7-Option to install additional fonts
8-Built in web apps
9-Download resume feature

Bolt browser is a great deal and it is free to install. The latest available version of bolt is 2.50. There are two options for data connection. One is socket and other is HTTP. The browser automatically detects that which type of connection is supported by your mobile phone.

Bolt is available for almost all mobiles. I am also using it and i am really impressed from it. Its most amazing feature is its ability to stream videos with great speed and without any buffering.
There are few disadvantages of this browser:
1-Sometimes it hangs up
2-Very poor and difficult to read fonts
3-Sometimes the streaming stops