Since you're already taking a CS course which involves Java, I would recommend you to keep learning it. Java's statically typed & OO nature forces you to learn a lot of important yet common programming fundamentles. C++, C# and Java type languages also force you write code more carefully (you have to think about the data types on your own and even allocate/de-allocate memories [C++ pointers]). That's why colleges prefer it as go to language for teaching CS concepts.

On the other hand, JS, Python and other such languages are dynamic in nature and hence, easy to learn. But you can't learn certain concepts (polymorphism, abstract classes, diamond problem etc) using these languages. So it makes sense to stick with Java in your case.