Requires java 21:

$ java --version
openjdk 21.0.1 2023-10-17 LTS

To run:

java Main.java

Use any editor or IDE to edit the koans in koans/*.java files

To exit press ^C, or finish all the koans.

• Covers mostly language, going in libraries only when needed

• Part 1 -> Structure of method

• Part 2 -> Structure of class/interface/records etc.

• Part 3 -> Structure of project

• Beginner/Intermediate/Advanced tag, and to run only one subset.
• export all java docs to a text file for reviewing the content
• cmd line arg to run specific method.

• Introduction to koans system
  • assert based test
  • compilation failure based test
• Local Variables
  • declarations
  • assignment
  • initialization
  • [-] uninitialized
• Primitive types & values
  • boolean
  • char
  • byte, short, int, long
  • float, double
  • [-] automatic type ('var')
• Reference Types and Values.
  • String
  • Boxed primitive
  • Objects, new
  • Object
  • null & NPE
• Parameterized types
  • List
  • Set
  • Dequeue
  • Map
  • Wildcard
• Arrays
  • types and variables
  • assignment
  • initializing
  • accessing
• Expressions
  • method calls
  • static method calls
  • method chaining
  • string concatanation
  • arithmatic operations
  • relational operations
  • conditional / ternary
  • assignment