The Codename One backend is not Spring compatible. We use similar syntax to ease migration and porting, but familiar annotations do not tell you whether the ported application behaves the same way. Tests do. What is Codename One? Codename One is an open-source framework for building native iOS, Android, desktop, and web apps from a single Java or Kotlin codebase. Learn more at codenameone.com . Write those tests in the original Spring application first. Capture the behavior your clients...