This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
Which of the following types can be added to java.util.Vector? A) reference B) null C) int D) All of the above The answer given in the mock are A, B. When I verified I am able to add null to Vector. Are there any other collection classes where I can add null?