This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum 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?