netbeans re-create build-impl.xml

netbeans - return the 'Libraries Folder' text box to its default state

in a netbeans java project -> properties -> library, there is a field called "libraries folder".  i selected a value for it and realized that i didn't need it.  i saw no way to remove it.  to remove it, find the file project.xml under the nbproject folder and remove this:

<libraries xmlns="http://www.netbeans.org/ns/ant-project-libraries/1">
            <definitions></definitions>
</libraries>

this creates a problem if you try to build your project.  the error is something like:

..\nbproject\build-impl.xml:63: Source resource does not exist: ..\nblibraries.properties

basically build-impl.xml is looking for the nblibraries property you had specified earlier.  the way to fix this is to delete and re-create the build-iml.xml

delete / remove build-impl.xml   close your project and then re-open your project.  the file will be re-created.