Netbeans 5.5.1/ 6.0 seems to be on some machines incredible slow. Adding an application server (etc. Glassfish) into the IDE can cause the freeze of the whole IDE. I observed this phenomenon on some Windows machines and was curious about the causes. In most case the slow performance is caused by the virus scanner. Adding an application into netbeans makes it scan all Java EE Jars which is actually really fast (few seconds). However on some machines with some paranoid virus scan settings it can take several minutes (every jar is checked for viruses).... I'm already wondering, what causes more damage - a virus, or working with an activated virus scanner:-).
Another performance problem is the "Slow File Dialog On Windows". Big zip files on window's desktop causes a significantly slow down of all file dialogs - sometime it can take almost a minute to open a file dialog...
On my machine (Vista 32 with Core Duo) Netbeans 6.0 is slightly slower, than 5.5.1 (especially startup) and so Eclipse 3.3 - however I'm maintaining many (30-50) projects in my workspace as well as several servers in parallel (2 Glassfish, JBoss and Weblogic 10).
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