Java
A portable, object-oriented language running on the JVM — used for Android apps, enterprise back-ends and large systems.
Java's motto is "write once, run anywhere": code compiles to bytecode that runs on any Java Virtual Machine. It is strongly typed, garbage-collected and fully object-oriented, with a huge standard library.
Sub-topics (10)
JDK, JRE and JVM
The Java Development Kit, Runtime Environment and Virtual Machine — what each one does.
Java Basics
The main method, primitive types, strings and control flow in Java.
Classes and Objects in Java
Fields, methods, constructors, access modifiers and the static keyword.
Inheritance in Java
extends, method overriding and super in Java.
Interfaces and Abstract Classes
Define contracts with interfaces and share partial implementations with abstract classes.
Exception Handling in Java
try/catch/finally, checked vs unchecked exceptions and try-with-resources.
Collections Framework
Lists, sets, maps and queues — Java's standard data structures.
Generics in Java
Type parameters make classes and methods work with any type while staying type-safe.
Multithreading in Java
Run tasks concurrently with threads and executors, and protect shared data with synchronisation.
Java Streams and Lambdas
Process collections declaratively with lambdas and the Stream API (Java 8+).
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