执行Maven Install时出现ClassLoader.defineClass访问性错误

核心问题 #

Spring Boot 2.7.7 + Java 17开发的登录系统，Eclipse直接运行正常，但执行mvn install时测试阶段抛出InaccessibleObjectException，提示module java.base does not "opens java.lang" to unnamed module。

解决方案 #

1. 配置Maven Surefire插件添加JVM参数 #

在pom.xml的<build><plugins>节点中添加Surefire插件配置，开放模块化系统的反射访问权限：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <configuration>
        <argLine>
            --add-opens java.base/java.lang=ALL-UNNAMED
            --add-opens java.base/java.lang.reflect=ALL-UNNAMED
        </argLine>
    </configuration>
</plugin>

Java 9+的模块化系统默认限制核心模块内部API的反射访问，Spring的CGLIB生成代理类时需要访问这些API，通过--add-opens参数可开放指定包给未命名模块（传统类路径依赖）。

2. 临时跳过测试（不推荐） #

若仅需快速完成打包，可执行以下命令跳过测试阶段：

mvn install -DskipTests

注意：此方法会跳过所有测试用例，不建议在正式开发流程中使用。

3. 优化依赖管理 #

移除tomcat-jasper的手动版本指定，让Spring Boot parent自动管理依赖版本，避免版本兼容性问题：

<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jasper</artifactId>
</dependency>

原因分析 #

Eclipse直接运行时，内置测试执行器可能自动添加了适配Java模块化的JVM参数；而Maven Surefire插件默认未添加这些参数，导致测试阶段Spring无法通过CGLIB生成代理类，触发访问权限错误。

原始问题信息 #

pom.xml配置 #

<?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>2.7.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>java-login-security</groupId>
    <artifactId>login-system</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>login-system</name>
    <description>login system</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <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>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jasper</artifactId>
            <version>9.0.70</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

错误日志片段 #

.   ____          _            __ _ _
 /\/ ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.7.7)

2023-01-14 12:19:00.834  INFO 2373 --- [           main] j.l.LoginSystemApplicationTests          : Starting LoginSystemApplicationTests using Java 17.0.4.1 on dna with PID 2373 (started by dna in /media/dna/data/koding/java/login-system)
2023-01-14 12:19:00.835  INFO 2373 --- [           main] j.l.LoginSystemApplicationTests          : No active profile set, falling back to 1 default profile: "default"
2023-01-14 12:19:01.333  INFO 2373 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2023-01-14 12:19:01.380  INFO 2373 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 41 ms. Found 1 JPA repository interfaces.
2023-01-14 12:19:01.530 ERROR 2373 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.cglib.core.CodeGenerationException: java.lang.reflect.InaccessibleObjectException-->Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain) throws java.lang.ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module @78dd667e
    at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:598) ~[spring-core-5.3.24.jar:5.3.24]
    at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:363) ~[spring-core-5.3.24.jar:5.3.24]
// ...more error log here...

Java版本信息 #

dna@dna:/$ java -version
openjdk version "17.0.5" 2022-10-18
OpenJDK Runtime Environment (build 17.0.5+8-Ubuntu-2ubuntu122.04)
OpenJDK 64-Bit Server VM (build 17.0.5+8-Ubuntu-2ubuntu122.04, mixed mode, sharing)

内容的提问来源于stack exchange，提问作者dhanyn10