Java course
Understand the idea. Try the code. Take one small step forward.
01—03 · Compilation & foundations
Use JDK 21 to study types, methods and arrays.
04—06 · Objects & validation
Understand encapsulation, generic collections and exceptions.
07—08 · Files & a project
Close resources correctly and build a study report.
Study the mechanism, run the example, then attempt the challenge before opening the solution. Every chapter includes verification and common boundaries.
Java: JDK, compilation and execution
Distinguish source code, bytecode and runtime and reproduce a first program.
Types, branches and loops
Recognize integer division, string comparison and loop boundaries.
Methods and arrays: explicit contracts
Extract reusable computation and understand parameters and return values.
Objects and encapsulation
Maintain object invariants through constructors and methods.
Collections, generics and sorting
Choose collection structures and produce deterministic summaries.
Exceptions and input validation
Separate malformed input, range failures and programming defects.
Files, UTF-8 and resource cleanup
Read and write text while closing resources on failure paths.
Project: a study-time report
Combine validation, collections and stable sorting while preserving rejected row numbers.