The Java Backend Developer's First 90 Days (en Inglés) - Elliot R. Westford

It begins with a service someone already depends on, a database with history, and a change that looks smaller on the ticket than it does in production.

The Java Backend Developer's First 90 Days gives you a practical way to enter that system without pretending you understand more than the evidence shows. Working through one Java 21 and Spring Boot service, you will learn how to trace behavior, identify the boundary that owns a decision, challenge a plausible fix, and hand off a bounded change another developer can inspect.

You will practice how to:

- reproduce an unfamiliar service and map one request end to end- choose tests that can disprove a claim- reason about tenant security, transactions, locks, retries, and idempotency- protect durable state with outbox, migration, and recovery decisions- investigate timeouts, saturation, metrics, workloads, and incidents>The book follows six phases of increasing responsibility across 24 chapters. It includes focused labs, four milestone assessments, eight diagrams, and 50 complete source-backed listings tied to a public companion project.

You should be comfortable writing ordinary Java methods, reading a stack trace, and running commands in a terminal. Prior professional experience with Spring, PostgreSQL, production operations, or distributed delivery is not required. Some advanced database exercises use disposable PostgreSQL; the initial service can run with H2.

This is not a framework encyclopedia or a promise that every team follows the same calendar. It is a field guide to becoming useful safely: understand the system, make the smallest defensible change, and earn trust with evidence.