I had an intermittent problem where Minecraft would freeze up on my Mac and just stop working. I would take anywhere from five to thirty seconds to unfreeze before I could start playing again. Some of the longer pauses would seem like a crash but it always eventually resumed. It was a nasty bug and extremely frustrating.
The root cause seems to be this bug in the JVM by Oracle for Mac OS X. The workaround is relatively simple. You need to add your hostname to the /etc/hosts file. This requires using the Terminal but it’s really pretty easy.
1. Open Applications > Utilities > Terminal.
2. Copy and paste the following command into the Terminal. This command appends your hostname to the /etc/hosts file and maps it to the IP address 127.0.0.1 (localhost). It will ask you for your password because you’re changing a system file.
sudo bash -c "echo 127.0.0.1 $HOSTNAME >> /etc/hosts"
3. Restart your Mac.
If that bug has been the cause of your freezes, hopefully this helps!