Good sources for learning JAVA?

I'm in my second to last semester in a webdev course. I'm taking a required class on algorithms and data structures, and although JAVA was not a prerequisite, (the prerequisite course used Python) it is becoming clear that I cannot pass this course without a working knowledge of it. I've spent a couple days watching YouTube videos and looking at online courses, but I'm more confused than ever. I'm usually a straight A student, and I have never in my life felt as utterly stupid and out of my depth as I do right now.

Can anyone recommend any videos, online courses, or books that are particularly good at explaining the basics of JAVA in an easy to understand way, without glossing over the whys of how things are done. In other words, I'd like something that explains each piece of code, not just "monkey see, monkey do." Thanks.