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Spring Boot 4 & Java 25 Backend Standards

General Rules

Always use targeted code blocks. Do not rewrite an entire class if only a method changes.
Never edit pom.xml or add Maven dependencies without asking for explicit permission first.

Tech Stack Constraints (CRITICAL)

Framework: Spring Boot 4.x (utilizing Spring Framework 7 and Jakarta EE 11 standards).
Java Version: Java 25 LTS. Take full advantage of modern features (e.g., Records, Switch Pattern Matching, Sequenced Collections, and Virtual Threads).
Packages: Use modern jakarta.validation and jakarta.persistence namespaces. Absolutely NO legacy javax packages.

Strict Java Code Style

Control Flow Braces: ALWAYS use explicit braces {} for control flow. Do not write single-statement if, else, for, while, or do-while loops on a single line without braces.
- DON'T: if (elem instanceof String s) out.add(s);
- DO: if (elem instanceof String s) { out.add(s); }

Architecture & Data Handling

Layered Pattern: Maintain strict isolation: Controller -> Service -> Repository -> Entity.
Data Transfer: Never expose database Entities directly to the controller layer. Always map database objects to explicit Data Transfer Objects (DTOs) or Java Records.
Validation: Enforce standard jakarta.validation annotations (e.g., @NotNull, @NotBlank) on all inbound controller DTOs/Records.

Compilation Guardrail (Token Burn Prevention)

If a Maven compilation or test suite build fails, STOP immediately. Report the exact console error log to the user. Do not try to guess or hallucinate fixes in a repetitive loop.