Basic
  1. Programming basics
  2. Introduction
  3. Basics
  4. Operators
  5. Loops
  6. Conditional statements
  7. Arrays
Intermediate
  1. OOP concept
  2. Scanner class - user input
  3. Inheritance and polymorphism
  4. Interfaces
  5. Data structures
  6. Overloading operators
  7. Useful methods, the Standard Library, and streams
  8. Instanceof keyword and downcasting
  9. Comparisons and the Object class
  10. Nested classes
  11. Documentation
  12. Enum type
Advanced
  1. Anonymous classes and Lambdas
  2. Record classes
  3. Exceptions
  4. Generic types and wildcards
  5. Regular expressions
  6. Threads
  7. Composition and aggregation
  8. Files
  9. ZIP files
  10. Using databases