Last Minute Notes

Start here for core Java: language fundamentals and OOP in Java, the collections framework, generics, lambdas and streams, multithreading, and how the JVM manages memory.

Start with Java Fundamentals

0 of 3 read

01
Java Fundamentals
Core Java language notes: types, strings, OOP in Java, exceptions, enums, records, and modern language features for interviews.
Table of Contents 1. The Java Platform 2. Data Types and Variables 3. Wrapper Classes and Autoboxing 4. Pass by Value 5. Strings 6. Control Flow and Modern Switch 7. Arrays 8. Classes, Constructors, and Initialization Order 9. Access Modifiers, static, and final 10. The Object Class: equals, hashCode, toString 11. Inheritance and Polymorphism in Java +10 more
02
Java Collections, Generics, and Streams
Java Collections Framework, HashMap internals, generics, lambdas, functional interfaces, streams, and Optional for interviews.
Table of Contents 1. Collections Framework Overview 2. List 3. Set 4. Queue and Deque 5. Map 6. HashMap Internals 7. Complexity Cheat Sheet 8. Sorting: Comparable vs Comparator 9. Iteration and Fail-Fast Behavior 10. Immutable and Unmodifiable Collections 11. Generics +6 more
03
Java Concurrency and JVM Internals
Threads, synchronization, the Java Memory Model, executors, CompletableFuture, virtual threads, JVM memory, garbage collection, and class loading for interviews.
Table of Contents 1. Threads Basics 2. Thread Lifecycle 3. Race Conditions and synchronized 4. wait, notify, and Deadlock 5. volatile and the Java Memory Model 6. Atomic Classes 7. Locks 8. Executor Framework and Thread Pools 9. CompletableFuture 10. Concurrent Collections 11. Synchronizers +9 more