add a box with clarification for java changes and restart (#1559)

Co-authored-by: Andre Meyering <[email protected]>
Co-authored-by: Mahati Shankar <[email protected]>

java/developing-applications/running.md

@@ -31,6 +31,10 @@ Once this is added, you can use the restart capabilities of the Spring Boot Devt
   * Artifacts generated from CDS (schema.sql, CSN, EDMX)
   * Any other static resource
 
+::: warning Restart for changed Java classes
+Spring Boot Devtools only detects changes to .class files. You need to enable the *automatic build* feature in your IDE which detects source file changes and rebuilds the .class file. If not, you have to manually rebuild your project to restart your CAP Java application.
+:::
+
 ### CDS Build
 
 The Spring Boot Devtools have no knowledge of any CDS tooling or the CAP Java runtime. Thus, they can't trigger a CDS build if there are changes in the CDS source files. For more information, please check the [Local Development Support](#local-development-support) section.