Java SE 7 & 8
Sometimes doing the right thing can be extremely difficult. In spite of and because of my commitment to Java, I had to decline an invitation to join the Java SE 7 and 8 expert groups. Talk about a tough decision!
Why did I decline? I'll contribute to open source projects and open standards, standards I can independently implement and license as open source. Java SE, with its anti-competitive licensing restrictions, is not an open standard. It doesn't belong in the thus far open JCP, and I can't support such a charade. I stand by Apache, and I hope Eclipse comes around.
I'm not a lawyer, but I can't help but wonder whether Oracle even has a right to apply additional licensing restrictions to the intellectual property in Java SE. Oracle didn't create Java SE on their own. Look at the list of JSRs pulled into Java SE 7 and SE 8 (see the Contributions sections). Look at the experts on those JSRs. Most of them aren't from Oracle. For example, JSR 310: Date and Time API comes from our own Stephen Colebourne.
The JSPA section 4.D protects experts in these situations, enabling them to withdraw their IP contributions if a spec lead, Oracle in the case of Java SE, changes the licensing terms:
Withdrawal of Contributions due to Change in Announced License Terms. If the Spec Lead for an Expert Group in which You are participating makes significant changes to the terms and conditions of any license granted pursuant to Sections 5.B or 5.F below after those terms and conditions are first disclosed pursuant to the Process, then You may, upon giving notice to the Specification Lead and the PMO, withdraw any copyright or patent licenses concerning Your Contributions granted pursuant to Section 4.A.I or 4.A.II above (but not patent licenses granted by You pursuant to Section 6 below).
It's not clear to me exactly how section 4.D applies to umbrella JSRs like Java SE, but I'd say that changes preventing independent open source implementations qualify as a "significant."