This question already has an answer here: How do I reset a lost administrative password? 13 answers I'm a new user of Ubuntu and I installed it on my computer using Virtual Box. I've been trying to install Java JDK for the past two hours without any success because when I try to do so, Terminal asks for my password, which I don't even remember creating. Can someone please help and tell me how am I suppose to change the password in order to install JDK? It will be very much appreciated, thank you.