diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc index 03ddaefd29..9d383bf5c5 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc @@ -24,6 +24,8 @@ To include devtools support, add the module dependency to your build, as shown i } ---- +CAUTION: Devtools might cause classloading issues, in particular in multi-module projects. <> explains how to diagnose and solve them. + NOTE: Developer tools are automatically disabled when running a fully packaged application. If your application is launched from `java -jar` or if it is started from a special classloader, then it is considered a "`production application`". You can control this behavior by using the `spring.devtools.restart.enabled` system property. @@ -40,6 +42,17 @@ When using the Gradle plugin, {spring-boot-gradle-plugin-docs}#packaging-executa +[[using.devtools.diagnosing-classloading-issues]] +=== Diagnosing Classloading Issues + +As described in the <> section, restart functionality is implemented by using two classloaders. +For most applications, this approach works well. +However, it can sometimes cause classloading issues, in particular in multi-module projects. + +To diagnose whether the classloading issues are indeed caused by devtools and its two classloaders, <>. If this solves your problems, <> to include your entire project. + + + [[using.devtools.property-defaults]] === Property Defaults Several of the libraries supported by Spring Boot use caches to improve performance. @@ -214,14 +227,11 @@ For IntelliJ IDEA, you can follow the https://www.jetbrains.com/help/idea/spring [[using.devtools.restart.customizing-the-classload]] ==== Customizing the Restart Classloader -As described earlier in the <> section, restart functionality is implemented by using two classloaders. -For most applications, this approach works well. -However, it can sometimes cause classloading issues. +As described earlier in the <> section, restart functionality is implemented by using two classloaders. If this causes issues, you might need to customize what gets loaded by which classloader. -By default, any open project in your IDE is loaded with the "`restart`" classloader, and any regular `.jar` file is loaded with the "`base`" classloader. -If you work on a multi-module project, and not every module is imported into your IDE, you may need to customize things. -To do so, you can create a `META-INF/spring-devtools.properties` file. +By default, any open project in your IDE is loaded with the "`restart`" classloader, and any regular `.jar` file is loaded with the "`base`" classloader. The same is true if you use `mvn spring-boot:run` or `gradle bootRun`: The project containing your `@SpringBootApplication` is loaded with the "`restart`" classloader, and everything else with the "`base`" classloader. +You can instruct Spring Boot to load parts of your project with a different classloader by creating a `META-INF/spring-devtools.properties` file. The `spring-devtools.properties` file can contain properties prefixed with `restart.exclude` and `restart.include`. The `include` elements are items that should be pulled up into the "`restart`" classloader, and the `exclude` elements are items that should be pushed down into the "`base`" classloader. The value of the property is a regex pattern that is applied to the classpath, as shown in the following example: