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Browse All Tracks
Python
135
Java
183
JavaScript
148
DSA
185
Database
117
System Design
78
DevOps
144
ML / AI
108
C / C++
65
C# / .NET
55
CS Fundamentals
73
PHP
55
Interview
76
Cheat Sheets
Guides
Tools
Interview Prep
Java Track
Java Tutorials
Master Java from basics to advanced OOP, collections, multithreading and Java 8+ features.
183
Topics
58
Beginner
87
Intermediate
38
Advanced
π Complete Java Guide β all 183 topics β
Java Basics
Introduction to Java
Beginner
JDK vs JRE vs JVM Explained
Beginner
Java Program Structure
Beginner
Data Types in Java
Beginner
Variables and Constants in Java
Beginner
Operators in Java
Beginner
Type Casting in Java
Beginner
Input and Output in Java
Beginner
Comments in Java
Beginner
Java Keywords and Identifiers
Beginner
Java Access Modifiers
Beginner
Java Wrapper Classes
Beginner
Autoboxing and Unboxing in Java
Intermediate
Control Flow
if-else Statement in Java
Beginner
switch Statement in Java
Beginner
for Loop in Java
Beginner
while and do-while Loop in Java
Beginner
break and continue in Java
Beginner
Nested Loops in Java
Beginner
Enhanced for Loop in Java
Beginner
Ternary Operator in Java
Beginner
Labeled break and continue in Java
Intermediate
Arrays
Arrays in Java
Beginner
Multi-dimensional Arrays in Java
Intermediate
Array Sorting in Java
Beginner
Array Searching in Java
Beginner
Arrays Class in Java
Intermediate
Jagged Arrays in Java
Intermediate
Copying Arrays in Java
Beginner
Sparse Arrays in Java
Advanced
OOP Concepts
Classes and Objects in Java
Beginner
Constructors in Java
Beginner
Inheritance in Java
Intermediate
Polymorphism in Java
Intermediate
Encapsulation in Java
Intermediate
Abstraction in Java
Intermediate
Interfaces in Java
Intermediate
Abstract Classes in Java
Intermediate
Method Overloading in Java
Beginner
Method Overriding in Java
Intermediate
super and this Keywords in Java
Intermediate
static Keyword in Java
Intermediate
final Keyword in Java
Intermediate
Object Class in Java
Intermediate
instanceof Operator in Java
Beginner
Nested and Inner Classes in Java
Intermediate
Strings
Strings in Java
Beginner
String Methods in Java
Beginner
StringBuilder and StringBuffer in Java
Intermediate
String Formatting in Java
Beginner
Regular Expressions in Java
Intermediate
String Comparison in Java
Beginner
String Immutability in Java
Intermediate
String Pool in Java
Advanced
String Tokenizer in Java
Intermediate
Character Class in Java
Beginner
Char Array to String in Java: Four Conversion Methods
Beginner
List to Comma Separated String in Java
Beginner
Java String contains(): Check for Substrings
Beginner
Java Split String: By Delimiter, Regex and Limit
Beginner
Java String replace(), replaceAll() and replaceFirst()
Beginner
Exception Handling
Exception Handling in Java
Intermediate
try-catch-finally in Java
Intermediate
Custom Exceptions in Java
Intermediate
throws and throw in Java
Intermediate
Checked vs Unchecked Exceptions
Intermediate
Multi-catch and Finally Block
Intermediate
Collections
Collections Framework Overview
Intermediate
ArrayList in Java
Intermediate
LinkedList in Java
Intermediate
HashMap in Java
Intermediate
HashSet in Java
Intermediate
TreeMap and TreeSet in Java
Intermediate
Stack and Queue in Java
Intermediate
Iterator and ListIterator in Java
Intermediate
LinkedHashMap and LinkedHashSet
Intermediate
PriorityQueue in Java
Intermediate
Comparable and Comparator in Java
Intermediate
Collections Utility Class in Java
Intermediate
Deque and ArrayDeque in Java
Intermediate
ConcurrentHashMap in Java
Advanced
EnumMap and EnumSet in Java
Intermediate
WeakHashMap in Java
Advanced
IdentityHashMap in Java
Advanced
Java flatMap(): Flatten Streams and Optional
Intermediate
HashMap vs Hashtable in Java
Beginner
Java Stream filter(): Filter Collections with Lambdas
Beginner
Java Map containsKey(): Check if a Key Exists
Beginner
Java 8+ Features
Lambda Expressions in Java
Intermediate
Stream API in Java
Intermediate
Optional Class in Java
Intermediate
Functional Interfaces in Java
Intermediate
Method References in Java
Intermediate
Default Methods in Interface
Intermediate
Date and Time API in Java 8
Intermediate
forEach and Map Operations in Stream
Intermediate
Collectors in Java Stream API
Advanced
var Keyword in Java 10
Beginner
Records in Java 16
Intermediate
Sealed Classes in Java 17
Advanced
Pattern Matching in Java
Advanced
CompletableFuture vs Future
Advanced
Text Blocks in Java 15
Beginner
Java 25 New Features β What Changed and Why Minecraft Upgraded
Intermediate
Multithreading
Multithreading in Java
Advanced
Thread Lifecycle in Java
Advanced
Synchronization in Java
Advanced
Executors and Thread Pools in Java
Advanced
volatile Keyword in Java
Advanced
Deadlock in Java
Advanced
wait notify and notifyAll in Java
Advanced
CompletableFuture in Java
Advanced
Atomic Classes in Java
Advanced
CountDownLatch and CyclicBarrier
Advanced
Java I/O
File Handling in Java
Intermediate
FileReader and FileWriter in Java
Intermediate
BufferedReader and BufferedWriter
Intermediate
Serialization in Java
Advanced
NIO in Java
Advanced
Working with JSON in Java
Intermediate
Java Scanner Class
Beginner
Java PrintWriter and PrintStream
Intermediate
Advanced Java
Generics in Java
Advanced
Reflection API in Java
Advanced
Annotations in Java
Intermediate
Enums in Java
Intermediate
Inner Classes in Java
Intermediate
Anonymous Classes in Java
Intermediate
Design Patterns in Java
Advanced
Singleton Pattern in Java
Intermediate
Factory Pattern in Java
Intermediate
Builder Pattern in Java
Intermediate
Garbage Collection in Java
Advanced
JVM Memory Model
Advanced
JVM Memory Issues in Production: Debugging Guide (OOM, GC, Leaks)
Intermediate
JVM GC Tuning Guide: G1, ZGC, Shenandoah Explained with Real Trade-offs
Intermediate
Observer Pattern in Java
Intermediate
Strategy Pattern in Java
Intermediate
Decorator Pattern in Java
Intermediate
Dependency Injection in Java
Advanced
Java Modules β JPMS
Advanced
Java Memory Leaks and Prevention
Advanced
Spring Boot Introduction
Intermediate
Maven vs Gradle in Java
Intermediate
Java Profiling and Performance
Advanced
Java Logging with SLF4J and Logback
Intermediate
Java Agent and Instrumentation
Advanced
JUnit 5 Annotations: @Test, @BeforeEach, @AfterEach and More
Beginner
Mockito verify(): How to Assert Method Calls in Unit Tests
Intermediate
Unit Testing vs Integration Testing: Key Differences
Beginner
Spring Boot
Spring Boot Application Properties Explained
Beginner
Spring Boot Project Structure
Beginner
Spring Boot Auto-Configuration Explained
Beginner
Building a REST API with Spring Boot
Beginner
Spring Boot Annotations Cheat Sheet
Beginner
Spring Boot with MySQL and JPA
Intermediate
Spring Boot Exception Handling
Intermediate
Spring Boot Validation with Bean Validation API
Intermediate
Spring Boot Security Basics
Intermediate
JWT Authentication with Spring Boot
Intermediate
Spring Boot Actuator and Monitoring
Intermediate
Spring Boot Testing with JUnit and Mockito
Intermediate
Spring Boot with Docker
Advanced
Microservices with Spring Boot and Spring Cloud
Advanced
Spring Boot Caching with Redis
Advanced
Hibernate & JPA
Introduction to Hibernate ORM
Beginner
Hibernate vs JPA β What's the Difference
Beginner
Hibernate Entity Mapping Explained
Beginner
One-to-Many and Many-to-Many in Hibernate
Intermediate
HQL vs JPQL vs Native SQL
Intermediate
Hibernate Caching β First and Second Level
Intermediate
Hibernate N+1 Problem and How to Fix It
Advanced
Build Tools
Maven Tutorial for Beginners
Beginner
Maven vs Gradle β Which Should You Use
Beginner
Understanding pom.xml in Maven
Beginner
Maven Dependency Management Explained
Intermediate
Gradle Build Script Basics
Beginner
Concurrency
Java Threads and Runnable Explained
Intermediate
Java Executor Service and Thread Pools
Intermediate
synchronized Keyword in Java
Intermediate
Java Locks and ReentrantLock
Advanced
Java CompletableFuture Explained
Advanced
Deadlock in Java β Causes and Prevention
Advanced