AP Computer Science A (CSA) - Java-Focused Exam Survival Guide

Must-do topics

• Java Basics: syntax, types, operators, if/else, loops.
• Classes & Objects: constructors, methods, instance variables, encapsulation.
• Arrays & ArrayLists: iteration, common algorithms (search, sort).
• Inheritance & Polymorphism: superclasses, method overriding, abstract classes.
• Algorithms: searching (linear, binary), sorting (selection, insertion, merge).
• Recursion: base case, recursive case, tracing calls.
• Exam FRQs & MCQs: trace code, debug, write short methods.

Top traps

• Forgetting == vs .equals() for strings.
• Array index off-by-one errors.
• Forgetting new keyword with objects.
• Misusing inheritance (constructor chaining).
• Writing recursion with no base case (infinite loop).

Quick checks

• Write method: return larger of two ints.
• Create array of 5 doubles and sum them.
• Class Dog with fields name, age → constructor + method bark().
• Recursion: factorial(4).
• Trace: what does arr[2] return?

You will make

• Java Syntax Cheat Sheet.
• Class/Method Skeleton Templates.
• Sorting Algorithm Card Deck (step by step).
• Recursion Trace Maps.
• Mini Java Project (student record manager or game).

Last-48 Hours Checklist — AP CSA (Java)

• Write down the class skeleton from memory: fields, constructor, methods.
• Drill string comparisons: == vs .equals() — 3 examples.
• Run 3 array/ArrayList practice loops (sum, search, insert).
• Trace 1 recursion problem (factorial, Fibonacci).
• Review sorting algorithms (selection, insertion, merge) step by step.
• Re-solve 2 past FRQs (no IDE, just pencil/paper).
• Memorize common runtime errors: null pointer, index out of bounds.
• Quick review: static vs instance methods; inheritance rules.