1. Uninstall previous version of Netbeans: Your default "uninstall.sh" file in the /home/userName/Netbeans7.x.x folder is doing this job.
2. Update your JRE and JDK: Before update, enter "java -version" into terminal to check your current version of JAVA.
3. To install OpenJDK 7, execute the following command:
sudo apt-get install openjdk-7-jre
This will install the Java Runtime Environment (JRE).
4. If you instead need the Java Development Kit (JDK), execute the following command:
sudo apt-get install openjdk-7-jdk
5. Run "netbeans-8.0.1-linux.sh" through the terminal.