Core Java
The foundation of every Java program. Before writing a Spring service or a reactive pipeline, you need a solid grip on Java's syntax, primitive types, operators, and control-flow constructs. This domain covers those building blocks from first principles.
What You'll Find Here
| Topic | Description |
|---|---|
| Variables & Data Types | The 8 primitive types, literals, var inference, constants, and final. |
| Type Conversion | Widening vs. narrowing casts, implicit numeric promotion in expressions. |
| Operators & Expressions | Arithmetic, bitwise, logical, ternary, and instanceof operators. |
| Control Flow | if/else, switch expressions (Java 14+), for, while, do-while. |
| Arrays | Single and multi-dimensional arrays, Arrays utility class. |
| Strings | Immutability, string pool, StringBuilder, and core String APIs. |
| Methods | Signatures, overloading, varargs, pass-by-value, recursion. |
| Packages & Imports | Package structure, imports, classpath basics, and access modifiers. |
Learning Path
- Start with Variables & Data Types — understand what the JVM can store before anything else.
- Move to Type Conversion — learn how Java promotes and casts between types.
- Cover Operators & Expressions — arithmetic, bitwise, and logical operators power every algorithm.
- Study Control Flow — branching and loops are the skeleton of every method.
- Read Arrays — fixed-size collections and the foundation of higher-level data structures.
- Study Strings —
String,StringBuilder, and string formatting are used in every program. - Finish with Methods and Packages & Imports before moving to Object-Oriented Programming.
Related Domains
- Object-Oriented Programming — builds directly on classes, fields, and methods introduced here.
- Java Type System — dives deeper into primitives, autoboxing, and generics.
- Core APIs — the
String,Math, and wrapper classes extend what you learn here.