I'm not sure when they lifted it but certainly in 1.4.0 it was 63 or 64 on Windows. I'm pretty certain this was fixed by 1.4.2. There was no restriction on other platforms that I'm aware of.
No, they added a system of sub-selectors that each handle 63 or 64 and communicate with the main selector via a java.nio.channels.Pipe. No limit now. What problem are you experiencing?