Technical proficiency
Check depth in modern Java (records, streams, virtual threads) plus Spring Boot, JPA/Hibernate, Maven or Gradle, and how they handle concurrency and garbage collection tuning.
Evidence to listen for
- Command of the languages, frameworks, and data tools the role actually uses
- Understands correctness, performance, and failure modes, not just syntax
- Has opinions on testing and can justify them
- Reads and reasons about code they did not write
Five-point scoring guide
Cannot work independently; fundamentals are missing.
Weak fundamentals; output needs heavy review.
Competent for the role; needs guidance on complex or unfamiliar work.
Strong practitioner; handles hard problems with little guidance.
Names JDK versions used, explains collection or concurrency choices precisely, and describes GC or heap tuning done on a real service.