Several developers, especially those familiar with equivalent functionality in Eclipse, have been asking for so-called "Save Actions", that is, support for actions that are automatically performed when a file is saved.

Here's the related NetBeans issue: http://netbeans.org/bugzilla/show_bug.cgi?id=140719  

In NetBeans IDE 7.3, the issue is resolved as follows:

1. A new "On Save" tab is found in the "Editor" tab of the Options window. Defaults for all languages are set via the "All Languages" item in the drop-down. Here, for all languages, you can specify what kind (all, none, or only modified lines) of formatting and space removal will occur automatically when a file is saved:

   

2. Via the drop-down, you see all the languages supported by the IDE:

   

3. You can pick a language and then override the default On Save settings:

   

4. Per language, there may be additional On Save settings. For example, for Java, you can specify that, when saving a Java file, unused import statements should be removed and/or the rules you've set for organizing import statements should be applied:

   

There's also a set of new NetBeans IDE APIs for adding new On Save functionality via custom plugins. Via MIME type registration of OnSaveTask.Factory, you can register new On Save actions that will be run for files conforming to the relevant MIME type. There's also extensions via the Editor Options API for registering new panels (one per language) to the On Save panel in the Options window. I'll demonstrate some examples of the APIs in upcoming blog entries.