java.lang.ArrayStoreException 阐明

这个demo来说明奈何排查一个spring boot 1应用进级到spring boot 2时大概呈现的java.lang.ArrayStoreException。

demo地点：https://github.com/hengyunabc/spring-boot-inside/tree/master/demo-ArrayStoreException

demo里有两个模块，springboot1-starter和springboot2-demo。

在springboot1-starter模块里，是一个简朴的HealthIndicator实现

public class MyHealthIndicator extends AbstractHealthIndicator {
	@Override
	protected void doHealthCheck(Builder builder) throws Exception {
		builder.status(Status.UP);
		builder.withDetail("hello", "world");
	}
}

@Configuration
@AutoConfigureBefore(EndpointAutoConfiguration.class)
@AutoConfigureAfter(HealthIndicatorAutoConfiguration.class)
@ConditionalOnClass(value = { HealthIndicator.class })
public class MyHealthIndicatorAutoConfiguration {
	@Bean
	@ConditionalOnMissingBean(MyHealthIndicator.class)
	@ConditionalOnEnabledHealthIndicator("my")
	public MyHealthIndicator myHealthIndicator() {
		return new MyHealthIndicator();
	}
}

springboot2-demo则是一个简朴的spring boot2应用，引用了springboot1-starter模块。

把工程导入IDE，执行springboot2-demo里的ArrayStoreExceptionDemoApplication，抛出的异常是

Caused by: java.lang.ArrayStoreException: sun.reflect.annotation.TypeNotPresentExceptionProxy
	at sun.reflect.annotation.AnnotationParser.parseClassArray(AnnotationParser.java:724) ~[na:1.8.0_112]
	at sun.reflect.annotation.AnnotationParser.parseArray(AnnotationParser.java:531) ~[na:1.8.0_112]
	at sun.reflect.annotation.AnnotationParser.parseMemberValue(AnnotationParser.java:355) ~[na:1.8.0_112]
	at sun.reflect.annotation.AnnotationParser.parseAnnotation2(AnnotationParser.java:286) ~[na:1.8.0_112]
	at sun.reflect.annotation.AnnotationParser.parseAnnotations2(AnnotationParser.java:120) ~[na:1.8.0_112]
	at sun.reflect.annotation.AnnotationParser.parseAnnotations(AnnotationParser.java:72) ~[na:1.8.0_112]
	at java.lang.Class.createAnnotationData(Class.java:3521) ~[na:1.8.0_112]
	at java.lang.Class.annotationData(Class.java:3510) ~[na:1.8.0_112]
	at java.lang.Class.createAnnotationData(Class.java:3526) ~[na:1.8.0_112]
	at java.lang.Class.annotationData(Class.java:3510) ~[na:1.8.0_112]
	at java.lang.Class.getAnnotation(Class.java:3415) ~[na:1.8.0_112]
	at java.lang.reflect.AnnotatedElement.isAnnotationPresent(AnnotatedElement.java:258) ~[na:1.8.0_112]
	at java.lang.Class.isAnnotationPresent(Class.java:3425) ~[na:1.8.0_112]
	at org.springframework.core.annotation.AnnotatedElementUtils.hasAnnotation(AnnotatedElementUtils.java:575) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.isHandler(RequestMappingHandlerMapping.java:177) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.initHandlerMethods(AbstractHandlerMethodMapping.java:217) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.afterPropertiesSet(AbstractHandlerMethodMapping.java:188) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping.afterPropertiesSet(RequestMappingHandlerMapping.java:129) ~[spring-webmvc-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1769) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1706) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	... 16 common frames omitted

利用 Java Exception Breakpoint

下面来排查这个问题。

在IDE里，新建一个断点，范例是Java Exception Breakpoint（假如不清楚怎么添加，可以搜索对应IDE的利用文档），异常类是上面抛出来的java.lang.ArrayStoreException。

当断点起效时，查察AnnotationUtils.findAnnotation(Class<?>, Class<A>, Set<Annotation>) line: 686函数的参数。

可以发明

说明是实验从MyHealthIndicatorAutoConfiguration里查找@Endpoint信息时堕落的。