NetBeans 7 (beta) is very slow on OS X

Problem: I downloaded the latest Netbeans 7 beta from and installed into my MacBook Pro. This Apple machine has Snow Leopard, dual core CPU, 2GB RAM and a lot of free spaces on its hard disk. When I change a letter A to B in my code or I am just doing nothing except staring at my code, seemingly without any good reason, NetBeans starts to scan my java projects for a few minutes and slows down the Mac so badly I cannot use it. The CPU usage is well over the roof of our appartmant and the hard disk goes tropical heat. Is it a beta issue? Should I switched to Eclipse? How to stop project scanning? Answer: Excessive file scanning is a NetBeans IDE issue from the very beginning. NetBeans must verify what files have been changed that affects our projects. If this verification process takes too long there is something wrong with our machine… or with the IDE scanning process. This symptom is likely a side effect of their choosen IDE design and it is not caused by our “slow” hardware or bad coding from their programmers. This Java IDE seems to randomly decide when and what needs to be rescanned. Nobody knows when it will be corrected if ever. Try out these steps: 1. Check out your Mac and project configuration. Repair file permissions. NetBeans is one of the hardest competitors in the use of the filesystem caches. All source files, libraries and modules… are verified for being up to date from filesystem point of view. This is often a very very long operation. Do not use network disks or folders in your project. 2. Use the ScanOnDemand plugin. Find Tools -> Plugins and search for Scan On Demand. By this plugin any attempt from the IDE to automatically detect external changes will be blocked. Manual refresh is available from File menu. This plugin is useful but not a cure at all. 3. Navigate to the netbeans.conf file and increase the allocated memory limits for the values of MaxPermSize and MaxPermSize. It often helps – by masking the reliability problem:
XX:PermSize=256m -J-XX:MaxPermSize=768m ..."
The netbeans.conf is in the NetBeans application bundle. Where is it? Run Finder. Find NetBeans in the Applications folder. Press Control and click on the file. Select Show Package Contents from the context menu. Locate the Contents -> Resources folder. The file is there. Edit with a text editor.