Why does NetBeans request a CA?
Oracle asks that you share the copyright on your contributions the first time you contribute code to netbeans.org, so that Oracle can protect the NetBeans code base and also allow consideration of alternative licensing models under a unified copyright for the netbeans.org code base.
Most importantly, having joint ownership of copyright allows Oracle to offer commercial, binary distributions of the NetBeans project. Without this ability, it would not be possible for Oracle to open its technologies, nor feasible to continue to invest in them as a business and employ developers working on the code.
See policy statement for more details at http://www.oracle.com/technetwork/oca-faq-405384.pdf