This is probably an IDE question, or the solution is in your IDE configuration, but I would think that if you installed the JDK correctly, BEFORE installin the IDE, the IDE should know where to find the core Java documentation. The IDE may be configured to obtain them online, so you may need to either have an Internet connection or the path corrected locally. In any case, I think you need someone smarter at Netbeans than me. You might try the Netbeans documentation and check your configuration or ask at the online forum, user groups, read the Wiki, etc.