JavaBean 解决 Error creating bean with name 'xxx' defined in javaconfig.

控制台报错如下：

    警告: Exception encountered during context initialization - cancelling refresh attempt
    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'newA' defined in javaconfig.JavaConfigTest: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javaconfig.A]: Factory method 'newA' threw exception; nested exception is java.lang.IllegalAccessError: tried to access class javaconfig.A from class $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1119)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1014)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
        at org.springframework.context.annotation.AnnotationConfigApplicationContext.(AnnotationConfigApplicationContext.java:84)
        at javaconfig.JavaConfigTest.main(JavaConfigTest.java:21)
    Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [javaconfig.A]: Factory method 'newA' threw exception; nested exception is java.lang.IllegalAccessError: tried to access class javaconfig.A from class $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
        ... 13 more
    Caused by: java.lang.IllegalAccessError: tried to access class javaconfig.A from class $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637
        at $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637.newA()
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162)
        ... 14 more

    Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'newA' defined in javaconfig.JavaConfigTest: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [javaconfig.A]: Factory method 'newA' threw exception; nested exception is java.lang.IllegalAccessError: tried to access class javaconfig.A from class $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1119)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1014)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
        at org.springframework.context.annotation.AnnotationConfigApplicationContext.(AnnotationConfigApplicationContext.java:84)
        at javaconfig.JavaConfigTest.main(JavaConfigTest.java:21)
    Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [javaconfig.A]: Factory method 'newA' threw exception; nested exception is java.lang.IllegalAccessError: tried to access class javaconfig.A from class $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
        ... 13 more
    Caused by: java.lang.IllegalAccessError: tried to access class javaconfig.A from class $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637
        at $javaconfig.JavaConfigTest$$EnhancerBySpringCGLIB$$bde62637.newA()
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162)
        ... 14 more

好，先上代码，

package javaconfig;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.AbstractApplicationContext;

@Configuration
public class JavaConfigTest {
    @Bean
    public A newA() {
        return new A();
    }

    @Bean
    public B newB() {
        return new B(newA());
    }

    public static void main(String[] args) {
        AbstractApplicationContext context = new AnnotationConfigApplicationContext(JavaConfigTest.class);
        B b = (B) context.getBean("newB");
        b.print();
    }
}
class A {
    @Override
    public String toString() {
        return "引入 A 类";
    }
}
class B {
    A a;

    B(A a) {
        this.a = a;
    }

    void print() {
        System.out.println("B 类的方法中" + a);
    }
}

检查过文件配置，全部是正确的，此时这样的代码出现报错情况，实际上是访问权限符有问题，我将以 @Bean 作为注解部分的 public 删除，程序即可正常运行。