Learn to Code in 7 days

Java / Beginner · Free and public

Learn Java in 7 Days

From your first message to a tested application with several source files. Read clear code, predict what it does, then write programs of your own.

Start your first lesson →

Start from zero. Build something useful.

No Python, JavaScript, account or installation required. Java and JavaScript are different languages. This path introduces each concept before asking you to use it independently.

36 lessons across seven modules. Allow about 60–90 minutes of active study per day, with extra time if you need it. Predict, run, change and explain each example; do the daily checkpoint before reading its solution. These are author estimates, not measured completion times. Split days across sessions freely.

Programs run in your browser using code-playpad 0.5.1, which implements a documented subset of Java 25. The course uses classic Main/main programs, supported library classes and flat source files. Each editor starts fresh. Input is supplied in the input box before Run; Java does not pause to wait for new answers here.

The final project runs in the browser and is downloadable for a real JDK. Local installation is optional. There is no file persistence, network service or account data in the Java project. Completion is saved in this browser only; it does not measure mastery.

Official Java learning resources · Playground documentation and compatibility

Day 1 · About 80 minutes

Your First Programs

Run Java, name values and explain numbers and text.

  1. Hello, Java 15 min · Read, predict and practise
  2. Variables & Types 15 min · Read, predict and practise
  3. Numbers & Arithmetic 15 min · Read, predict and practise
  4. Strings & Messages 15 min · Read, predict and practise
  5. Checkpoint: Study Budget 20 min · Independent checkpoint

Day 2 · About 80 minutes

Decisions & Loops

Choose branches and trace bounded repetition.

  1. if / else if / else 15 min · Read, predict and practise
  2. Boolean Logic 15 min · Read, predict and practise
  3. for Loops 15 min · Read, predict and practise
  4. while Loops 15 min · Read, predict and practise
  5. Checkpoint: Weekly Goal 20 min · Independent checkpoint

Day 3 · About 80 minutes

Methods & Small Checks

Break a problem into methods and verify their results.

  1. Methods 15 min · Read, predict and practise
  2. Parameters & Arguments 15 min · Read, predict and practise
  3. Return Values 15 min · Read, predict and practise
  4. Scope & Small Checks 15 min · Read, predict and practise
  5. Checkpoint: Session Pricing 20 min · Independent checkpoint

Day 4 · About 80 minutes

Arrays & Lists

Store, traverse and summarize groups of values.

  1. Arrays & Indexes 15 min · Read, predict and practise
  2. Array Loops 15 min · Read, predict and practise
  3. ArrayList 15 min · Read, predict and practise
  4. String Tools & Equality 15 min · Read, predict and practise
  5. Checkpoint: Plan Summary 20 min · Independent checkpoint

Day 5 · About 80 minutes

Objects & Source Files

Model independent objects and connect classes in separate files.

  1. Classes & Objects 15 min · Read, predict and practise
  2. Constructors & this 15 min · Read, predict and practise
  3. Private State & Methods 15 min · Read, predict and practise
  4. Multiple Source Files 15 min · Read, predict and practise
  5. Checkpoint: Session State 20 min · Independent checkpoint

Day 6 · About 80 minutes

Input, Validation & Errors

Read input, reject invalid values and test recovery.

  1. Scanner & Standard Input 15 min · Read, predict and practise
  2. Validation & Parsing 15 min · Read, predict and practise
  3. Exceptions & Recovery 15 min · Read, predict and practise
  4. Tests & Regression Checks 15 min · Read, predict and practise
  5. Checkpoint: Input Recovery 20 min · Independent checkpoint

Day 7 · About 80 minutes

Build a Study Planner

Run, test and extend a complete multi-file Java application.

  1. Study Planner 15 min · Read, predict and practise
  2. Project Tests 15 min · Read, predict and practise
  3. Run Java Locally 15 min · Read, predict and practise
  4. Extend the Planner 15 min · Read, predict and practise
  5. On Your Own: Reading Tracker 20 min · Independent checkpoint
  6. Come Back Later 25 min · Come back in a few days · extra review