Java. Lang. Reflect. MalformedParameterizedTypeException: null
At sun. Reflect. Generics. ReflectiveObjects. ParameterizedTypeImpl. ValidateConstructorArguments (ParameterizedTypeImpl. Java: 58) ~ [na: 1.8.0 comes with _221]
At sun. Reflect. Generics. ReflectiveObjects. ParameterizedTypeImpl. & lt; init> (ParameterizedTypeImpl. Java: 51) ~ [na: 1.8.0 comes with _221]
At sun. Reflect. Generics. ReflectiveObjects. ParameterizedTypeImpl. Make (ParameterizedTypeImpl. Java: 92) ~ [na: 1.8.0 comes with _221]
At sun. Reflect. Generics. Factory. CoreReflectionFactory. MakeParameterizedType (CoreReflectionFactory. Java: 105) ~ [na: 1.8.0 comes with _221]
At sun. Reflect. Generics. Visitor. Reifier. VisitClassTypeSignature (Reifier. Java: 140) ~ [na: 1.8.0 comes with _221]
At sun. Reflect. Generics. Tree. ClassTypeSignature. Accept (ClassTypeSignature. Java: 49) ~ [na: 1.8.0 comes with _221]
At sun. Reflect. Generics. Repository. ConstructorRepository. GetParameterTypes (ConstructorRepository. Java: 94) ~ [na: 1.8.0 comes with _221]
The at Java. Lang. Reflect. The Executable. GetGenericParameterTypes (283). The Executable Java: ~ [na: 1.8.0 comes with _221]
The at Java. Lang. Reflect. Method. GetGenericParameterTypes (283) Method. The Java: ~ [na: 1.8.0 comes with _221]
The at Java beans. FeatureDescriptor. GetParameterTypes (FeatureDescriptor. Java: 387) ~ [na: 1.8.0 comes with _221]
The at Java beans. MethodDescriptor. SetMethod (MethodDescriptor. Java: 116) ~ [na: 1.8.0 comes with _221]
The at Java beans. MethodDescriptor. & lt; init> (MethodDescriptor. Java: 72) ~ [na: 1.8.0 comes with _221]
The at Java beans. MethodDescriptor. & lt; init> (MethodDescriptor. Java: 56) ~ [na: 1.8.0 comes with _221]
The at Java beans. Introspector. GetTargetMethodInfo (Introspector. Java: 1205) ~ [na: 1.8.0 comes with _221]
The at Java beans. Introspector. GetBeanInfo (Introspector. Java: 426) ~ [na: 1.8.0 comes with _221]
The at Java beans. Introspector. GetBeanInfo (Introspector. Java: 173) ~ [na: 1.8.0 comes with _221]
At the groovy. Lang. MetaClassImpl $15. The run (MetaClassImpl. Java: 2940) ~ [groovy - 1.7.5. Jar: 1.7.5]
The at Java. Security. The AccessController. DoPrivileged (Native Method) ~ [na: 1.8.0 comes with _221]
At the groovy. Lang. MetaClassImpl. AddProperties (MetaClassImpl. Java: 2938) ~ [groovy - 1.7.5. Jar: 1.7.5]
At the groovy. Lang. MetaClassImpl. The initialize (MetaClassImpl. Java: 2921) ~ [groovy - 1.7.5. Jar: 1.7.5]
The at org. Codehaus. Groovy. Reflection. ClassInfo. GetMetaClassUnderLock (ClassInfo. Java: 166) ~ [groovy - 1.7.5. Jar: 1.7.5]
The at org. Codehaus. Groovy. Reflection. ClassInfo. GetMetaClass (ClassInfo. Java: 182) ~ [groovy - 1.7.5. Jar: 1.7.5]
The at org. Codehaus. Groovy. Runtime. Metaclass. MetaClassRegistryImpl. GetMetaClass (MetaClassRegistryImpl. Java: 210) ~ [groovy - 1.7.5. Jar: 1.7.5]
The at org. Springframework. Beans. Factory. Groovy. GroovyBeanDefinitionReader. & lt; init> (GroovyBeanDefinitionReader. Java: 150) ~ [spring - beans - 5.2.8. The jar: 5.2.8. RELEASE]
The at org. Springframework. Boot. BeanDefinitionLoader. & lt; init> (BeanDefinitionLoader. Java: 85) ~ [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at org. Springframework. Boot. SpringApplication. CreateBeanDefinitionLoader (SpringApplication. Java: 738) [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at org. Springframework. Boot. SpringApplication. Load (SpringApplication. Java: 681) [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at org. Springframework. Boot. SpringApplication. PrepareContext (SpringApplication. Java: 392) [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at org. Springframework. Boot. SpringApplication. Run (SpringApplication. Java: 314) [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at org. Springframework. Boot. SpringApplication. Run (SpringApplication. Java: 1237) [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at org. Springframework. Boot. SpringApplication. Run (SpringApplication. Java: 1226) [spring - the boot - 2.3.2. The jar: 2.3.2. RELEASE]
The at cn.net.withub.mail.CqMailProjectApplication.main (CqMailProjectApplication. Java: 16)/classes/: na
below is springboot pom
Wsdl4j & lt;/groupId> Wsdl4j & lt;/artifactId> 1.5.1 & lt;/version> Taglibs Standard 1.1.2 & lt;/version> Com. McHange C3p0 & lt;/artifactId> 0.9.2.1 & lt;/version> Org. Springframework. Boot Spring - the boot - starter - web Org. Springframework. Boot Spring - the boot - starter - tomcat Org. Springframework. Boot Spring - the boot - starter - jdbc