- Spring Boot – Elasticsearch
Full-text search that a LIKE query cannot do. Spring Data Elasticsearch repositories, mapping a document, keeping the index in step with the database, and being honest about the operational cost — this is the point where the demo app stops needing only MySQL.
- Python – Lambda Functions
The one-expression anonymous function. Where it belongs — a sort key, a small callback — where it does not, and why `sorted(xs, key=lambda p: p.name)` is the example that justifies the whole feature.
- Java 17 Records
A record is a class whose job is to carry data. You declare the components; the compiler writes the constructor, the accessors, equals , hashCode and toString . One line replaces about sixty. The sixty lines it replaces Every one of those hand-written members is a place a bug can hide — an equals…
- Java 11 Removed/Deprecated Features & Migration
Java 11 is the upgrade that breaks things. Not because the language changed — it barely did — but because Java 11 removed several modules that had been part of the JDK since the 1990s. Most upgrades from 8 fail for the same handful of reasons, and they are all fixable. Why this one hurts Java 9…
- Hash Tables
Turn the key into an array index and go straight there. Separate chaining, the load factor, why resizing has to rehash rather than copy, what a bad hashCode does to your O(1), and the equals/hashCode contract that breaks lookups when you get it wrong.