NetBeans Quick Tip #17 - Faster Building of Projects with Dependencies
By Roman Strobl on XI 08, 2005
Last time I wrote about using dependent projects. I mentioned one drawback of using them: slower compilation time. There's a way to avoid it, you can choose in the main project's properties that the other projects do not get built automatically. Then you need to rebuild them manually when you do changes, but your compile time is again short.
To achieve this, just uncheck the Build projects on Classpath checkbox in Libraries section of project properties: