Working on Java JSP JSTL Web Application.

Things have been working fine for several weeks.

Last couple of days, I can not make proper build.

When I make changes to a file and press save the browser shows the changes.

But when I press Clean and Build to get my dist/WAR updated, it fails to build
with
Deleting directory C:\Users\gdd030\Documents\NetBeansProjects\FieldNotifications\build
C:\Users\gdd030\Documents\NetBeansProjects\FieldNotifications\nbproject\build-impl.xml:1433: Unable to delete file C:\Users\gdd030\Documents\NetBeansProjects\FieldNotifications\build\web\WEB-INF\lib\eclipselink.jar
BUILD FAILED (total time: 3 seconds)

I then press the Build button, and netbeans creates the new WAR file with the current date, but the file changes are lost.

Building jar: C:\Users\gdd030\Documents\NetBeansProjects\FieldNotifications\dist\FieldNotifications.war
do-dist:
dist:
BUILD SUCCESSFUL (total time: 1 second)

I checked the History tab and saw that there was a datetime where the changes are correct, but the current version has lost changes. 

I rebooted and now the History does not show the changes anymore and the date is older.

Not sure what to do.

I don't know if this is because of the failed build trying to remove the eclipselink.jar and I don't know how the eclipselink.jar got in my lib directory. Should I get rid of it manually?