Why does Sun want to dual license NetBeans under CDDL and GPLv2?
The GPL v2.0 license will provide an additional option to vendors that are unable to work with NetBeans under the CDDL license.
Adding GPLv2 as a license option makes NetBeans more Linux friendly.
Adding GPLv2 with Classpath exception to NetBeans keeps product portfolios and bundles consistent. Sun Microsystems open-sourced its JDK implementation under GPLv2 and the GlassFish project is dual-licensed under CDDL and GPLv2 with Classpath exception.