I recently updated my early 2011 MacBook Pro to Mac OS X 10.7.5. The new update (combo ~2GB) took hours of download in my slow connection. I was happy when the download completed, so i installed the update and rebooted the Mac. Normally, new update should bring new improvements over performance, bug fixing and new features but this time my Mac became slow and sometimes it freezed while i was using Safari, Chrome or Finder.
After doing some searching on Google, i managed to find the solution. There was a discussion on Apple support site, the solution was to update Java/JDK to JDK7. So i downloaded JDK7 and installed it, it really fixed the problem. There is no freezing anymore and it gets faster then before.
One drawback is, Java plugin for Chrome will not work. It is because Chrome is 32 bit browser and it does not support Java 7. So if you are heavily using Chrome with java plugin, it is not recommended to update to Java 7. But if you are already using Java 7 but want to get back to Java 6 (pre-installed with Mac Os) you can follow this guide to restore Java 6.