How We Increased Code Coverage by 28% Without Writing a Single Test

A Salesforce engineer on the Security Mesh platform increased code coverage by 28% without writing any new tests by restructuring Java data models. The approach involved replacing @Data-annotated mutable classes with immutable Java records and @Value annotations, removing auto-generated boilerplate (getters, setters, utility methods) that inflated coverage denominators without representing real business logic. The Builder pattern was introduced to handle object enrichment while preserving immutability. This reduced total measured lines of code, naturally improving the coverage ratio. The post also discusses how excessive boilerplate harms AI-assisted development tools by consuming context window space and reinforcing false system contracts.