Go and the go std lib are licensed under a bsd license, which is a more liberal license than java and the jdk and would avoid things like the oracle lawsuit against android.
So yes, just because it's open source doesn't mean much, but it's open source with a very liberal license, which does mean something.
Originally, the Oracle lawsuit had some patent claims in it, IIRC. They were thrown out though. I can't recall if they were thrown out by the judge or if Google spent the time/money/lawyers to get them invalidated.
IANAL, I don't think that's true for the Apache license, because it includes a clause that explicitly reassigns patents (or at least licenses any relevant patents).
Java is open source by the completely literal meaning of this word, but it is not in the spirit of open source, i.e. it is not free software (as was recently demonstrated by Oracle's lawsuit).
In case you're forgetting history, Java only went open source very recently (2007, only really usable in 2008)[0]. For much of its life, it has been a closed source language / runtime.
Nothing against Java, now, but it's not a fair comparison to Go. (Disclosure: I was an early Go contributor but no longer use it for day to day work. I have no affiliation with Google.)
