Most students think ArrayLists are “just arrays but nicer”… and that’s exactly why their code breaks. Arrays are rigid. ArrayLists are flexible. Different rules. Different tools. Different behaviors. Once you stop treating them like the same thing, you finally understand why one uses brackets, the other uses methods, and why your bugs keep coming from mixing the two. Follow for more Java clarity, and DM for AP Computer Science help. 💻⚡️ | Daniel Finley - The AP Computer Science Tutor

The biggest ArrayList bugs don’t come from the code… they come from treating ArrayLists like they’re just “better arrays.” They’re not. Arrays follow one set of rules. ArrayLists follow a completely different set. And the moment you mix the two — using brackets on an ArrayList, expecting it to resize, calling the wrong length method — your program falls apart. The students who win are the ones who learn the differences, not just the syntax. Follow for more Java clarity, and DM for AP Computer Sc

AP Computer Science A: How Hard Is It And What It Covers