This repository is a curated collection of Java interview questions and answers, organized by topics such as Core Java, Collections, Concurrency, Spring, Hibernate, SQL, and more. It also includes several small, self-contained Java projects that demonstrate specific concepts: a custom Stream API implementation (custom-stream), a deadlock example (deadlock), a set of LeetCode algorithm solutions (leetcode-221-maximal-square), and a flawed code review snippet (review). The primary value is the extensive markdown documentation with links to external resources, making it a useful study aid for Java interview preparation. The code examples are educational but not production-grade; the custom-stream project is the most notable for illustrating the internal pipeline pattern of Java Streams. The repository is static and has not been actively updated in some time, though the content remains relevant for many core Java topics.