Dec 24, 2025 · 9 min read · I remember my first Java interview. The interviewer asked: "Which collection would you use to store unique user IDs with fast lookup?" I froze. ArrayList? HashMap? HashSet? They all sounded right. And wrong. I mumbled something about ArrayList, added...
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May 1, 2025 · 7 min read · Most devs think they understand equals() and hashCode(). They don’t. They override one and forget the other. Furthermore, they assume a working HashMap means a correct one. They let mutability creep into keys. And then act surprised when retrieval fa...
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Apr 28, 2025 · 3 min read · Starting from this post, I'm shifting gears.The next few blogs will be purely technical — heavier, sharper, with no extra storytelling. HashMap looks simple on the surface.But when you go under the hood, especially after Java 8, it’s clear it wasn’t ...
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Apr 10, 2025 · 7 min read · Thread-Safe Collections in Java: ConcurrentHashMap vs Synchronized Collections Thread safety is a crucial consideration when working with collections in multi-threaded Java programs. ConcurrentHashMap and synchronized collections are two of Java's ma...
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Apr 5, 2025 · 3 min read · [60] Java Collection Framework The Java Collection Framework is a set of classes and interfaces in Java that provide commonly reusable, type-safe and efficient data structures to store and manipulate group of objects. The framework consists of severa...
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Feb 12, 2025 · 37 min read · Phần 1: Tổng quan về Java Collection Framework (20 câu) 1. Java Collection là gì? Trả lời: Là một framework cung cấp các cấu trúc dữ liệu và thuật toán để lưu trữ và xử lý dữ liệu một cách hiệu quả. 2. Những thành phần chính trong Collection Framewor...
Join discussionFeb 12, 2025 · 19 min read · Phần 1: Kiến thức nội bộ và nâng cao Collection Framework (20 câu) 1. HashMap hoạt động nội bộ như thế nào? Trả lời: HashMap sử dụng bảng băm (hash table). Các key được chuyển đổi thành giá trị hashCode(), từ đó xác định vị trí lưu trữ trong bucket....
Join discussionJan 26, 2025 · 15 min read · It's better to understand the fundamentals of DSA before diving into Java collections. Data Structures: They define how data is organized and stored. This impacts how efficiently you can access, insert, and delete elements within that structure. Al...
Join discussionNov 29, 2024 · 37 min read · In the world of programming, data is king. Everything we design, every application we build, revolves around efficiently managing and processing data. From a simple list of tasks in a to-do app to managing millions of customer records in an enterpris...
Join discussionNov 18, 2024 · 13 min read · Imagine you're in a busy kitchen, using different tools to prepare a meal—this is similar to the Java Collections Framework. It provides a set of classes and interfaces to store, manage, and retrieve data in your programs. Just like you have differen...
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