The 'Validation failed for query for method' error in Spring Data JPA is a startup-time fail-fast mechanism triggered by invalid @Query declarations. Three common causes are covered: using SQL reserved keywords (like GROUP) as column names without escaping, referencing database column names instead of Java field names in JPQL, and writing native SQL without setting nativeQuery=true. Each pitfall is demonstrated with a broken query and a corrected version, verified using @DataJpaTest integration tests.
Table of contents
1. Introduction2. Understanding the Root Cause3. Common Pitfalls and Solutions4. ConclusionSort: