Core Java — Study Notes

A structured collection of beginner-friendly Core Java notes covering fundamental concepts from the ground up. Each topic is documented with explanations, examples, and tables to support learning and quick revision.

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Java_Basics

Foundational Java topics organized sequentially, from how the JVM works to advanced beginner concepts like wrapper classes.

• JavaBasics_01.md — Compiler vs Interpreter | JVM | Bytecode Covers the Java compilation and execution pipeline: writing .java source code, compiling with javac, generating .class bytecode, and running it on the JVM.

• JavaBasics02.md — Platform Independence | Classes & Objects Explains platform dependence vs independence, the Write Once Run Anywhere (WORA) principle, introduction to classes and objects, and the Java execution flow.

• JavaBasics03_java-data-types-and-variables-notes.md — Data Types & Variables Covers all 8 primitive data types and their memory sizes, non-primitive (reference) types, variable declaration and initialization, and static vs non-static variables.

• JavaBasics04_java-methods-notes.md — Methods Covers method syntax and components, access modifiers (public, private, protected, default), types of methods, parameter passing, return types, and an introduction to method overloading.

• JavaBasics05_java_strings.md — Strings Covers String creation, String Pool memory management, immutability, common String methods, concatenation, StringBuilder vs StringBuffer, formatting, conversion, and regular expressions.

• JavaBasics06_java-packages-and-naming-conventions-notes.md — Packages & Naming Conventions Covers Java packages as directory-based code organization, package and import statements, predefined vs user-defined packages, the java.lang default package, and Java naming conventions.

• JavaBasics07_java-operators-notes.md — Operators Covers all Java operator types: arithmetic, unary, assignment, relational/comparison, logical/conditional, bitwise, shift, ternary (? :), and the instanceof operator.

• JavaBasics08_control-flow-and-switch-statement.md — Control Flow & Switch Statement Covers sequential vs conditional execution, if, if-else, if-else-if chains, and the switch statement including enhanced switch expressions.

• JavaBasics09_java-looping-and-branching-statements-notes.md — Looping & Branching Statements Covers for, while, and do-while loops, and branching/jumping statements: break, continue, and return.

• JavaBasics10_user-dynamic-input-java-notes.md — User Dynamic Input Covers reading runtime input from the user using the Scanner class, why dynamic input is preferred over hardcoding values, and common nextInt(), nextLine(), etc. methods.

• JavaBasics11_arrays-in-java-notes.md — Arrays Covers arrays as fixed-size reference types, declaration and initialization, single-dimensional and multi-dimensional arrays, array traversal, and common array operations.

• JavaBasics12_command-line-arguments-java.md — Command Line Arguments Covers passing values to a Java program at runtime via String[] args in the main method, accessing and using those arguments, and practical use cases.

• JavaBasics13_wrapper-classes-java.md — Wrapper Classes Covers the 8 wrapper classes (Integer, Double, Character, etc.), why they are needed in Collections, autoboxing and unboxing, null support, and utility methods for conversion and comparison.