This article outlines a set of best practices to help you avoid problems and build reliable persistence layers with Kotlin and Jakarta Persistence. And to share some good news before diving in, IntelliJ IDEA 2026.1 will automatically detect many of these issues, highlight them with warnings, and provide support through various inspections.

Kotlin is a modern programming language developed by JetBrains, designed to interoperate with Java and run on the Java Virtual Machine (JVM). With features like null safety, type inference, and extension functions, Kotlin offers a concise and expressive syntax for building robust and scalable applications. Developers can learn Kotlin's language features, explore its ecosystem of libraries and frameworks, and leverage Kotlin for developing Android apps, server-side applications, and multi-platform projects.

Kotlin

Jakarta Persistence (JPA) was designed for Java, creating friction with Kotlin's defaults like final classes, immutable properties, and null safety. To build reliable persistence layers, avoid data classes for entities, use regular open classes with mutable properties, configure the no-arg and all-open compiler plugins, stick to field-based access, and make all entity fields nullable (including primary keys with generated values). Default values in constructors won't apply when loading from the database. Kotlin 2.2 improves annotation placement, and IntelliJ IDEA 2026.1 will detect these issues automatically with inspections and quick-fixes.

How to Avoid Common Pitfalls With JPA and Kotlin