The same Spring Boot 4.1 app written package-by-layer and package-by-feature, with the public surface counted, the compiler boundary captured and the component-scanning trap shown.
60 Java viva questions and answers covering basics, OOP, exceptions, collections, threads and JDBC, each with a runnable example and its real output.
10 Spring Boot project ideas for a resume with MVP scope, stretch goals, data models and the guides to build them; the cores of three ideas (URL shortener, rate limiter, expense splitter) are real, runnable code.
A Spring Boot 4.1 tutorial for beginners: set up, run your first app, understand controllers, services and repositories, configuration and validation, then follow a map of 80+ deeper guides.
Spring Framework, Spring MVC and Spring Boot explained by building the same endpoint twice: plain Spring MVC with manual Tomcat vs Spring Boot, with startup time, beans and jar size measured.
A grouped list of the Spring Boot annotations you will actually use, plus the pairs people confuse (@Component vs @Bean, @Controller vs @RestController, @Primary vs @Qualifier) with real output.
Every Spring Boot version from 2.0 to 4.1 with real release dates, free and commercial support end dates, Java baselines, the upgrade path from 2.7 and 3.5, and how to check your version.
30 pattern programs in Java with real output, the row/column logic table and the code for each: pyramids, diamonds, Floyd's and Pascal's triangle, hollow shapes and a method for any pattern.
25 array problems for Java interviews with brute-force and optimal solutions, complexity for each and real output: second largest, rotation, duplicates, missing number, two sum, Kadane and more.
Bubble, selection and insertion sort in Java with pass-by-pass traces, early-exit bubble sort, measured comparison and swap counts, stability and a comparison table.