Java Diagrams Generator with modular step-based configuration

Generate comprehensive Java project diagrams through a modular, step-based interactive process that covers UML sequence diagrams, UML class diagrams, C4 model diagrams, UML state machine diagrams, and ER (Entity Relationship) diagrams using PlantUML syntax. This is an interactive SKILL.

What is covered in this Skill?

• UML sequence diagram generation for application workflows and API interactions
• UML class diagram generation for package structure and class relationships
• C4 model diagram generation at Context/Container/Component levels only (levels 1–3; Code/Level 4 not generated)
• UML state machine diagram generation for entity lifecycles and business workflows
• ER diagram generation from SQL schema (DDL, migrations) using PlantUML Chen notation
• PlantUML syntax for all diagram types
• File organization strategies: single-file, separate-files, or integrated with existing documentation
• Final diagram validation with PlantUML syntax checking

Constraints

Before applying any diagram generation, ensure the project validates. If validation fails, stop immediately — do not proceed until all validation errors are resolved.

• MANDATORY: Run ./mvnw validate or mvn validate before applying any diagram generation
• SAFETY: If validation fails, stop immediately — do not proceed until all validation errors are resolved
• BEFORE APPLYING: Read the reference for detailed good/bad examples, constraints, and safeguards for each diagram generation pattern
• C4 LIMIT: C4 diagrams restricted to levels 1, 2, 3 only (Context, Container, Component); never generate Level 4 (Code) diagrams

When to use this skill

• Generate UML diagram
• Create sequence diagram
• Create class diagram
• Create state machine diagram
• Create C4 diagram
• Generate ER diagram

Workflow

1. Validate project state

Run ./mvnw validate or mvn validate before applying any diagram generation.

Step constraints:

• If validation fails, stop and ask to resolve errors first

2. Read reference and configure diagram scope

Read references/033-architecture-diagrams.md, identify requested diagram types, and confirm output organization strategy (single-file, separate-files, or integrated docs).

3. Generate PlantUML diagrams

Create requested diagrams in PlantUML syntax (sequence, class, C4 levels 1-3 only, state machine, ER) using project inputs and context.

Step constraints:

• Never generate C4 Level 4 (Code) diagrams

4. Validate and finalize outputs

Check generated diagrams for syntax correctness and consistency with selected scope before final delivery.

Reference

For detailed guidance, examples, and constraints, see references/033-architecture-diagrams.md.