Mr. Adiletta

Computer Science in Java

Java, from the first line you type to the algorithms that sort a collection of ten thousand things. Modeled on the four units of the AP® Computer Science A exam, with a question bank flush with practice problems — tagged to the same objectives the exam is written against — to get you ready for a 5.

Start Unit 1Assignments

The course

Start here, then four units

College Board rebuilt this course for Fall 2025: ten units became four. Below is that framework — 56 topics, each unit carrying its own weight on the exam, with a prologue in front that isn't on the exam at all.

00lockedHow the Machine ThinksBefore you write a line of Java, you should know what a computer actually is: switches, numbers built out of switches, and a set of tools that will not think for you — ending with a real Java project you created and ran.Inside · 19 min read
  1. What makes something a program
  2. Gates: how switches make a decision
  3. How can wires and electricity think?
  4. Build the tables yourself
  5. Counting in binary
  6. Hexadecimal, and why anyone bothers
  7. and 3 more
8 quick checksannotated specimenabstraction ladderstepperlogic gate scroller
01lockedUsing Objects and Methods15–25% of the examBy the end of this unit you can read a line of Java out loud, say what every piece of it does, and predict what it prints before you run it.Inside · 21 min read
  1. 1.1 · Algorithms, Programs, and the Compiler
  2. 1.2 · Variables and data types
  3. 1.3 · Expressions and output
  4. 1.4 · Assignment statements and input
  5. 1.5 · Casting and Numeric Limits
  6. 1.6 · Compound assignment operators
  7. and 10 more
50 quick checksannotated specimenscrollytellingobject reference diagramsobject instantiation yard02lockedSelection and Iteration25–35% of the examBuild Magpie — a chatbot that reads what a person typed and answers it — and in doing so learn the two things that turn a list of instructions into a program that responds to the world: decisions, and repetition.Inside · 34 min read
  1. The project · Magpie
  2. 2.1 · Algorithms That Decide and Repeat
  3. 2.2 · Boolean expressions
  4. 2.3 · if Statements
  5. 2.4 · Nested if Statements
  6. 2.5 · Compound Boolean expressions
  7. and 9 more
39 quick checksannotated specimenstepperloop tracerchatbot sandboxtruth tables+2 more03lockedClass Creation10–18% of the examBuild MonsterBattle — a turn-based fight you can play — starting with the Monster class underneath it, written by you from nothing and fought in a text-only battle first, deciding what an object knows, what it can do, and what it refuses to let anyone touch.Inside · 33 min read
  1. The projects · Monster, then MonsterBattle
  2. 3.1 · Designing with Abstraction
  3. 3.2 · The Consequences of Programs
  4. 3.3 · The Parts of a Class
  5. 3.4 · Constructors
  6. 3.5 · Writing Methods
  7. and 6 more
35 quick checksannotated specimenstepperobject reference diagramstext battle sandboxobject instantiation yard+2 more04lockedData Collections30–40% of the examBuild four things that each hold thousands of values at once — a dataset you parse, a photograph you edit pixel by pixel, a playable 2048 and a sorting bench — and learn the arrays, ArrayLists, 2D arrays and algorithms underneath all four.Inside · 47 min read
  1. What you will build
  2. 4.1 · Privacy, bias, and data quality
  3. 4.2 · Working with Data Sets
  4. 4.3 · Creating and Indexing Arrays
  5. 4.4 · Array traversals
  6. 4.5 · Standard Array Algorithms
  7. and 16 more
65 quick checksannotated specimenvideoArrayList sandboxloop tracercall stack viewer+3 more

Every day

The Do Now

One multiple-choice question, sometimes two, waiting when you sit down. Same tags College Board uses, so a miss tells you exactly which objective to go back to. 244 posted so far.

All assignments

How you're measured

5 thinking practices

The exam tests what you can do, not what you can recite: plan a program, write code, trace code, explain code and computing systems, use computing responsibly. Every question here is tagged with the practice it exercises. There are 12 skills, from 1.A to 5.A.

Outside this site

Practice, not more reading

  • CodingBat — short, focused method problems with instant right/wrong feedback.
  • SoloLearn — a phone-friendly Java course for reviewing between assignments.
  • Codecademy — a slower, guided walk through Java for a topic that didn't stick.