Java: Complete Language Course

How Java compilation and the JVM work

JDK vs JRE vs JVM, compilation steps, bytecode, class files, platform independence, javac command

Java primitive data types and variable declaration

int, long, double, float, boolean, char, byte, short, variable declaration, type sizes, default values

Java operators and expression evaluation order

arithmetic operators, comparison operators, logical operators, assignment operators, operator precedence, short-circuit evaluation, integer division

Java if-else and switch control flow

if statement, else-if chain, nested conditionals, switch statement, switch expression, fall-through, break, default case

Java for loop, while loop, and loop control

for loop syntax, while loop, do-while loop, enhanced for-each loop, break, continue, nested loops, infinite loop prevention

Java classes and objects explained

class definition, fields, methods, constructors, object instantiation, new keyword, this keyword, method signatures

Java encapsulation with private fields and getters setters

access modifiers, private fields, public getters, public setters, data hiding, validation in setters, encapsulation principle

Java inheritance and the extends keyword

extends keyword, superclass, subclass, method inheritance, constructor chaining with super, method overriding, @Override annotation, is-a relationship

Java polymorphism and method overriding at runtime

runtime polymorphism, dynamic dispatch, upcasting, downcasting, instanceof check, abstract classes, abstract methods

Java interfaces and implementing multiple contracts

interface definition, implements keyword, multiple interfaces, default methods, functional interfaces, interface vs abstract class, contract programming

Java ArrayList vs LinkedList — when to use each

ArrayList, LinkedList, List interface, dynamic resizing, index access, insertion performance, iteration, List.of, mutable vs immutable lists

Java HashMap and HashSet for fast lookups

HashMap, HashSet, Map interface, Set interface, key-value pairs, hash function, O(1) lookup, duplicate handling, null keys, entrySet iteration

Java generics and type-safe collections

generic classes, generic methods, type parameters, bounded type parameters, wildcards, type erasure, raw types, compile-time safety

Java Streams API for collection processing

Stream creation, filter, map, reduce, collect, sorted, distinct, findFirst, method references, lazy evaluation, terminal vs intermediate operations

Java Iterator pattern and Comparable for sorting

Iterator interface, hasNext, next, Iterable, Comparable, compareTo, Comparator, Collections.sort, custom sort order, natural ordering

Java checked vs unchecked exceptions explained

Exception hierarchy, Throwable, Error, checked exceptions, unchecked exceptions, RuntimeException, throws declaration, compiler enforcement, common exceptions

Java try-catch-finally and multi-catch blocks

try block, catch block, finally block, multi-catch, exception variable, exception message, stack trace, re-throwing, try-with-resources preview

Java try-with-resources and AutoCloseable

try-with-resources, AutoCloseable, Closeable, resource declaration, automatic close, suppressed exceptions, multiple resources, custom AutoCloseable

Reading and writing text files in Java

FileReader, FileWriter, BufferedReader, BufferedWriter, Files.readAllLines, Files.writeString, Path, Paths, NIO.2, charset, line separator

Custom exceptions in Java — when and how to create them

custom exception class, extending Exception vs RuntimeException, constructors, exception message, chained exceptions, domain-specific errors, exception hierarchy design

Java threads — creating and starting threads

Thread class, Runnable interface, lambda threads, thread lifecycle, start vs run, thread name, daemon threads, Thread.sleep, join method

Java synchronized keyword and race conditions

race condition, critical section, synchronized method, synchronized block, intrinsic lock, monitor, visibility problem, mutual exclusion, thread safety

Java ExecutorService and thread pool basics

ExecutorService, Executors factory, thread pool, fixed pool, cached pool, submit, Future, Callable, shutdown, awaitTermination, task queue

Java atomic classes and concurrent collections

AtomicInteger, AtomicLong, AtomicReference, CAS operation, ConcurrentHashMap, CopyOnWriteArrayList, BlockingQueue, ArrayBlockingQueue, thread-safe collections

Java CompletableFuture for async non-blocking code

CompletableFuture, supplyAsync, thenApply, thenAccept, thenCompose, exceptionally, allOf, anyOf, async pipeline, ForkJoinPool, non-blocking chaining

Java lambda expressions and functional interfaces

lambda syntax, functional interface, @FunctionalInterface, Predicate, Function, Consumer, Supplier, BiFunction, method references, type inference

Java Optional — avoiding NullPointerException properly

Optional creation, of, ofNullable, empty, isPresent, get, orElse, orElseGet, map, flatMap, filter, ifPresent, Optional anti-patterns, return type usage

Java records for immutable data classes

record syntax, canonical constructor, compact constructor, accessor methods, equals and hashCode, toString, record limitations, when to use records, record vs class

Java sealed classes and pattern matching with switch

sealed class, permits clause, sealed interface, final subclasses, record patterns, switch pattern matching, exhaustiveness checking, algebraic data types

Java design patterns — Builder, Strategy, and Observer

Builder pattern, method chaining, immutable objects, Strategy pattern, interchangeable algorithms, Observer pattern, event listeners, open-closed principle, separation of concerns