springboot Devtools isn't recompiling against the target Java version

Hello,

I have the --enable-preview argument enabled, and targeting Java 14 in my pom.xml file.

java -version                                                                                                                   
openjdk version "14-ea" 2020-03-17
OpenJDK Runtime Environment (build 14-ea+18-Ubuntu-1)
OpenJDK 64-Bit Server VM (build 14-ea+18-Ubuntu-1, mixed mode, sharing)

I'm able to build and run my Spring boot application without any issues, but whenever the code changes and the devtools kick in, the code gets recompiled against Java 13 instead.

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.6.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.example</groupId>
  <artifactId>example</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>example</name>
  <description>Example</description>

  <properties>
    <java.version>14</java.version>
    <snippetsDirectory>${project.build.directory}/generated-snippets</snippetsDirectory>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <scope>runtime</scope>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-configuration-processor</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
      <exclusions>
        <exclusion>
          <groupId>org.junit.vintage</groupId>
          <artifactId>junit-vintage-engine</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <jvmArguments>
            --enable-preview
          </jvmArguments>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <release>14</release>
          <compilerArgs>
            --enable-preview
          </compilerArgs>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

After triggering any change, I get:

java.lang.UnsupportedClassVersionError: com/example/ExampleRepository (class file version 57.65535) was compiled with preview features that are unsupported. This version of the Java Runtime only recognizes preview features for class file version 58.65535
    at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[na:na]
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016) ~[na:na]
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151) ~[na:na]
    at java.base/java.net.URLClassLoader.defineClass(URLClassLoader.java:514) ~[na:na]
    at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:422) ~[na:na]
    at java.base/java.net.URLClassLoader$1.run(URLClassLoader.java:416) ~[na:na]
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:691) ~[na:na]
    at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:415) ~[na:na]
    at org.springframework.boot.devtools.restart.classloader.RestartClassLoader.findClass(RestartClassLoader.java:159) ~[spring-boot-devtools-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.devtools.restart.classloader.RestartClassLoader.loadClass(RestartClassLoader.java:141) ~[spring-boot-devtools-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
    at java.base/java.lang.Class.forName0(Native Method) ~[na:na]
    at java.base/java.lang.Class.forName(Class.java:420) ~[na:na]
    at org.springframework.util.ClassUtils.forName(ClassUtils.java:285) ~[spring-core-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport.loadRepositoryInterface(RepositoryConfigurationExtensionSupport.java:389) ~[spring-data-commons-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport.getRepositoryConfigurations(RepositoryConfigurationExtensionSupport.java:94) ~[spring-data-commons-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.data.repository.config.RepositoryConfigurationDelegate.registerRepositoriesIn(RepositoryConfigurationDelegate.java:148) ~[spring-data-commons-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.data.repository.config.RepositoryBeanDefinitionRegistrarSupport.registerBeanDefinitions(RepositoryBeanDefinitionRegistrarSupport.java:107) ~[spring-data-commons-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.lambda$loadBeanDefinitionsFromRegistrars$1(ConfigurationClassBeanDefinitionReader.java:385) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:723) ~[na:na]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsFromRegistrars(ConfigurationClassBeanDefinitionReader.java:384) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:148) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:120) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:331) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:236) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:706) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532) ~[spring-context-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.6.RELEASE.jar:2.2.6.RELEASE]
    at com.example.main(ExampleApplication.java:13) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.2.6.RELEASE.jar:2.2.6.RELEASE]

It looks like the devtools isn't honoring the Java version in pom.xml when recompiling the source file. I couldn't find a parameter to set the Java version for the devtools either.

Comment From: snicoll

@HusseinElMotayam devtools does not recompile anything. I guess you're triggering the changes from your IDE using a "build project" action. Can you please check its configuration?

Comment From: HusseinElMotayam

Thank you @snicoll It turned out that my IDE wasn't properly configured.