- Spring Boot – JPA and Hibernate
Entities, relationships and the persistence context. Lazy loading and the N+1 query it hands you, why open-in-view is switched off here, soft deletes with @SQLRestriction, and the ddl-auto setting to use once something other than Hibernate owns your schema.
- Python – Conditional Statements
if, elif and else, what Python considers falsy and why that surprises people, the conditional expression, chained comparisons, and when `match` is genuinely clearer than a chain of elifs.
- Optional
Optional is a container that either holds a value or is empty. Its purpose is not to eliminate null — it is to move "there might be nothing here" out of your head and into the type signature, where the compiler and the next reader can both see it. The problem it solves Nothing forces a caller of…
- Terraform – What It Is and Why It Exists
Start here. What infrastructure as code actually buys you over clicking around a console, where Terraform sits next to CloudFormation, CDK, Pulumi and Ansible, the 2023 licence change and what OpenTofu is, the exact versions this track is written against, the application the AWS lessons deploy, and the full lesson index in reading order.
- React Native – Navigation
Navigation is not a router over URLs — it is a stack of native screens. Expo Router makes the folder structure the navigation graph: `(tabs)` groups without adding a URL segment, `[orderId]` declares a dynamic route, `+not-found` catches the rest. Stacks versus tabs, passing and reading params, `push` versus `replace`, and why route files should be one line long.