Optimizing Java Applications with Spring Boot 2.7 and JDK 17: Features, Migration Steps, and Deployment Practices

The article explores how to optimize and accelerate Java applications by using Spring Boot 2.7 together with JDK 17, analyzing new Spring Boot features, JDK 17 performance improvements, and their synergistic effects for developers.

Why Spring Boot 2.7? Spring Boot 2.7 serves as a transition version for JDK 17 adoption, offering support for new language constructs (switch expressions, text blocks, var), leveraging JDK 17 garbage collectors, thread scheduling, and security enhancements, while providing default configurations compatible with JDK 17.

Why JDK 17? JDK 17 introduces sealed classes, enhanced reflection permissions, stronger package‑scan controls, and the ZGC garbage collector, all of which contribute to better security and performance.

The article also presents a performance benchmark comparing GC behavior on JDK 8, 11, and 17, showing the advantages of ZGC.

OpenJDK 17 download : https://adoptium.net/zh-cn/temurin/releases/?version=17&os=linux&arch=x64

Spring Boot 2.7 pom.xml example : <?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.jd.magnus</groupId> <artifactId>magnus-multi-ddd</artifactId> <version>1.0.0-SNAPSHOT</version> <packaging>pom</packaging> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.7.17</version> </parent> <modules> <module>magnus-multi-ddd-adapter</module> <module>magnus-multi-ddd-application</module> <module>magnus-multi-ddd-domain</module> <module>magnus-multi-ddd-infrastructure</module> <module>magnus-multi-ddd-client</module> <module>magnus-multi-ddd-worker</module> </modules> <properties> <maven.compiler.source>17</maven.compiler.source> <maven.compiler.target>17</maven.compiler.target> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> </project>

Dynamic configuration changes – the auto‑configuration file path moved from META-INF/spring.factories to META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports , and a new @SpringBootApplication annotation simplifies setup.

Deprecated classes and methods (e.g., SpringBootServletInitializer , ServletWebServerFactoryCustomizer , BasicErrorController ) are listed with their recommended replacements.

Unit‑test migration – JUnit 4 annotations ( org.junit.Test ) are replaced by JUnit Jupiter ( org.junit.jupiter.api.Test ), and parameterized tests now use @ParameterizedTest and @ValueSource .

JVM parameters for ZGC (example for a 4C8G instance): -Xms5324m -Xmx5324m -XX:MaxMetaspaceSize=256m -XX:MetaspaceSize=256m \ -XX:MaxDirectMemorySize=983m -Djava.library.path=/usr/local/lib -server \ -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/export/Logs \ -Djava.awt.headless=true -Dsun.net.client.defaultConnectTimeout=60000 \ -Dsun.net.client.defaultReadTimeout=60000 -Djmagick.systemclassloader=no \ -Dnetworkaddress.cache.ttl=300 -Dsun.net.inetaddr.ttl=300 -XX:+UseZGC

Compatibility add‑opens for modules such as SGM, R2M, DUCC, AKS, Pfinder, etc. (example): --add-opens java.base/sun.security.action=ALL-UNNAMED --add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.math=ALL-UNNAMED --add-opens java.base/java.util=ALL-UNNAMED ... (other entries omitted for brevity)

Swagger compatibility fix – add spring.mvc.pathmatch.matching-strategy=ant_path_matcher to application.properties and register a BeanPostProcessor that filters handler mappings (code shown in the original source).

DDD scaffolding support – the internal JD Magnus DDD archetype now supports Spring Boot 2.7.17 and JDK 17. Generation command: mvn archetype:generate \ -DarchetypeGroupId=com.jd.magnus \ -DarchetypeArtifactId=magnus-multi-ddd-archetype \ -DarchetypeVersion=1.0.0-SNAPSHOT \ -DinteractiveMode=false \ -DarchetypeCatalog=remote \ -Dversion=1.0.0-SNAPSHOT \ -DgroupId=com.jdl.sps \ -DartifactId=bff-demo1

The article concludes that the combination of Spring Boot 2.7 and JDK 17 provides better performance, security, and compatibility, and that the internal services have been successfully trialed on the cloud platform with no major issues, paving the way for future migration to Spring Boot 3.0.