Server Memory Leak

I run a 1.9 server on my own computer and when I run it with the batch file (the command I'm running is the exact command that's on minecraft.net: java -Xmx1024M -Xms1024M -jar minecraft_server.jar nogui) after maybe 2 -3 hours my frame rate drops from a constant 60 to 10 and 0 every few seconds. I then check my task manager and it says memory is 96% - 100% (constantly fluctuating) I then have to restart my computer and then its fixed when I start it back up then restart 2 hours later then 2 more then 2 more etc. This has been annoying me for a while now so please fix it. I also wasn't sure if this was the right place to put this.