This repository contains five apps we (@joshlong and @mraible) used to figure out how to make Spring Native work with JHipster.

• spring-native-webflux - no client, no db, just WebFlux

• spring-native-mvc - no client, no db, just Spring MVC

• angular-webflux - Angular client, no db

• postgres-webflux - Angular, WebFlux, R2DBC + PostgreSQL

• postgres-mvc - Angular, Spring MVC, JPA + PostgreSQL

You should be able to create a JHipster monolith with OIDC, then make the following changes.

1. Modify pom.xml to add native, adjust dependencies, and disable devtools:

   <repository>
       <id>spring-releases</id>
       <name>Spring Releases</name>
       <url>https://repo.spring.io/release</url>
       <snapshots>
           <enabled>false</enabled>
       </snapshots>
   </repository>
   
   <pluginRepository>
       <id>spring-releases</id>
       <name>Spring Releases</name>
       <url>https://repo.spring.io/release</url>
       <snapshots>
           <enabled>false</enabled>
       </snapshots>
   </pluginRepository>
   ...
   
   <repackage.classifier/>
   <spring-native.version>0.10.4</spring-native.version>
   ...
   
   <!-- Comment out devtools -->
   <!--dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-devtools</artifactId>
       <optional>true</optional>
   </dependency-->
   
   <!-- If reactive, add the following to fix NoClassDefFoundError: org/springframework/web/servlet/config/annotation/WebMvcConfigurer -->
   <!-- Answer from https://stackoverflow.com/a/67426209/65681 -->
   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-web</artifactId>
       <exclusions>
           <exclusion>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-tomcat</artifactId>
           </exclusion>
       </exclusions>
   </dependency>
   ...
   
   <!-- Springfox doesn't have support for Spring Native yet, so comment out Springfox dependencies -->
   <!-- https://github.com/springfox/springfox/issues/3816 -->
   ...
   
   <!-- If reactive, comment out boringssl. This allows Spring Native to build the image and gets around this error:
       Error: Classes that should be initialized at run time got initialized during image building:
       io.netty.buffer.UnpooledUnsafeDirectByteBuf the class was requested to be initialized at run time
       (subtype of io.netty.buffer.AbstractReferenceCountedByteBuf).
       To see why io.netty.buffer.UnpooledUnsafeDirectByteB got initialized use
       trace-class-initialization=io.netty.buffer.UnpooledUnsafeDirectByteBuf
   -->
   <!--dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-tcnative-boringssl-static</artifactId>
   </dependency-->
   
   <dependency>
       <groupId>org.springframework.experimental</groupId>
       <artifactId>spring-native</artifactId>
       <version>${spring-native.version}</version>
   </dependency>
   
   <plugin>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-maven-plugin</artifactId>
       <configuration>
           <classifier>${repackage.classifier}</classifier>
           <image>
               <builder>paketobuildpacks/builder:tiny</builder>
               <env>
                   <BP_NATIVE_IMAGE>true</BP_NATIVE_IMAGE>
               </env>
           </image>
       </configuration>
   </plugin>
   <plugin>
       <groupId>org.springframework.experimental</groupId>
       <artifactId>spring-aot-maven-plugin</artifactId>
       <version>${spring-native.version}</version>
       <executions>
           <execution>
               <id>test-generate</id>
               <goals>
                   <goal>test-generate</goal>
               </goals>
           </execution>
           <execution>
               <id>generate</id>
               <goals>
                   <goal>generate</goal>
               </goals>
           </execution>
       </executions>
   </plugin>
   
   <profile>
       <id>native</id>
       <properties>
           <repackage.classifier>exec</repackage.classifier>
           <native-buildtools.version>0.9.3</native-buildtools.version>
       </properties>
       <dependencies>
           <dependency>
               <groupId>org.graalvm.buildtools</groupId>
               <artifactId>junit-platform-native</artifactId>
               <version>${native-buildtools.version}</version>
               <scope>test</scope>
           </dependency>
       </dependencies>
       <build>
           <plugins>
               <plugin>
                   <groupId>org.graalvm.buildtools</groupId>
                   <artifactId>native-maven-plugin</artifactId>
                   <version>${native-buildtools.version}</version>
                   <executions>
                       <execution>
                           <id>test-native</id>
                           <phase>test</phase>
                           <goals>
                               <goal>test</goal>
                           </goals>
                       </execution>
                       <execution>
                           <id>build-native</id>
                           <phase>package</phase>
                           <goals>
                               <goal>build</goal>
                           </goals>
                       </execution>
                   </executions>
               </plugin>
           </plugins>
       </build>
   </profile>

2. Remove the 127.0.0.1 prefix from keycloak.yml

3. Delete spring-logback.xml and tone down logging

   logging:
     level:
       root: ERROR

4. If reactive, update LocaleConfiguration.java to remove @Import(WebFluxAutoConfiguration.class)

5. Update main App.java to add hints (first four of each list only required for reactive)

   @NativeHint(options = "--enable-url-protocols=http,https")
   @TypeHint(
       types = {
           ReactiveOAuth2AuthorizedClientManager.class,
           ReactiveOAuth2AuthorizedClientProviderBuilder.class,
           DefaultReactiveOAuth2AuthorizedClientManager.class,
           AbstractWebClientReactiveOAuth2AccessTokenResponseClient.class,
           liquibase.configuration.LiquibaseConfiguration.class,
           com.zaxxer.hikari.HikariDataSource.class,
           liquibase.change.core.LoadDataColumnConfig.class,
           org.HdrHistogram.Histogram.class,
           org.HdrHistogram.ConcurrentHistogram.class,
       },
       typeNames = {
           "org.springframework.web.reactive.function.client.DefaultWebClientBuilder",
           "reactor.core.publisher.Traces$StackWalkerCallSiteSupplierFactory",
           "reactor.core.publisher.Traces$SharedSecretsCallSiteSupplierFactory",
           "reactor.core.publisher.Traces$ExceptionCallSiteSupplierFactory",
           "com.zaxxer.hikari.util.ConcurrentBag$IConcurrentBagEntry[]"
       },
       access = AccessBits.ALL)

6. Liquibase is not supported yet, but you can make it work by adding files from this pull request to your src/main/resources/META-INF/native-image/liquibase directory

7. Add an @AotProxyHint for each Resource classes

   @AotProxyHint(targetClass = UserResource.class, proxyFeatures = ProxyBits.IS_STATIC)
   @AotProxyHint(targetClass = BlogResource.class, proxyFeatures = ProxyBits.IS_STATIC)
   @AotProxyHint(targetClass = PostResource.class, proxyFeatures = ProxyBits.IS_STATIC)
   @AotProxyHint(targetClass = TagResource.class, proxyFeatures = ProxyBits.IS_STATIC)

8. If using Spring WebFlux, refactor repositories and add @AotProxyHint for each one

9. If using Spring MVC, swap Undertow dependencies for Tomcat, modify WebConfigurer to comment out setLocationForStaticAssets(server), and add additional type hints for the following classes:

   • tech.jhipster.domain.util.FixedPostgreSQL10Dialect.class

   • org.hibernate.type.TextType.class

10. Build with ./mvnw package -Pnative,prod -DskipTests

• Springfox (Swagger) doesn’t work

• Metrics don’t work

• Repositories need refactoring for R2DBC