As far as computer music playback software is concerned, a quick google search should throw up a good few examples of decent gapless supporting players, certainly for bog standard WAV files. The better players should definitely support gapless with other lossless formats too, such as the compressed FLAC & ALAC (Apple lossless) and Apple's uncompressed AIFF. I use the excellent free Foobar2000 music file player on my Windows computers, as it's highly configurable with a wealth of plug-in components and has a very decent support community. However, it can be a bit 'klunky' to those who are new to it.
Unfortunately, it's quite rare for a UPnP/DLNA streaming bluray player to support gapless playback. Even mainstream hifi stereo streamers have had the same problem and fortunately the majority now have gapless support, but only after firmware updates, eg's: Denon DNP-720AE, Marantz NA7004, Pioneer N-30 & N-50 & Cambridge Audio NP30 & Stream Magic 6, etc. Finding a solution to your bluray player's lack of gapless support will possibly depend on its UPnP/DLNA capabilities and will almost certainly not be very elegant.
You could merge all the album tracks into one file, as suggested by Arnold, as this should definitely work. However, losing the individual tracks will mean you'll no longer easily be able to locate individual movements within your classical music albums, for example. You'll also need to take into account the time taken to merge all the tracks of the required albums in your collection, not forgetting that unless you keep a copy of the original files, the process will be nigh on irreversable should you go on to acquire a gapless supporting streamer.
There's another possible solution that does not alter your cd file rips, but uses specialised computer sound capture software to create a UPnP/DLNA streamable music file, very similar to an internet radio file. Hence if your music player software is playing the tracks without any gaps, the captured sound will too. It's the UPnP/DLNA equivalent of Apple's Airplay. However, by nature these files are of unknown length, a feature which will need to be supported by your bluray player's streaming mechanism - but it's certainly worth trying. If your computer is a Windows machine, there's a couple of free applications you could give a go.
Firstly there's the free foo_UPnP plugin component available for Foobar2000 music player I mentioned, that gives Fb2k full UPnP/DLNA streaming capabilities, providing a UPnP/DLNA controller, server and renderer. However, what's relevant here is it also has the option of creating a UPnP/DLNA streamable file from the playlist of music tracks that's currently being played by Fb2k.
The other application to investigate is a UPnP/DLNA music server that captures the sound of the current application to create a UPnP/DLNA streamable file with, ie, it can be used for ANY music playing application. This is the free ('donation ware') Stream What You Hear UPnP/DLNA server.
Note that these streaming methods require the music data to be buffered, so there is a noticeable delay of usually 1-3 seconds when controlling the music playback. For example, the music will carrying on playing on the streamer for a few seconds after hitting pause on the computer's music player software.