Problem details:

When starting the project, an error is reported:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'searchIPAttributionService' defined in file [***\service\SearchIPAttributionService.class]: 
Instantiation of bean failed; nested exception is java.lang.ExceptionInInitializerError
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1013)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:959)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:626)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
	at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:651)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:599)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
	at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:518)
	at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:459)
	at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
	at javax.servlet.GenericServlet.init(GenericServlet.java:158)
	at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1284)
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1197)
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1087)
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5266)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5554)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1263)
	at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1948)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ExceptionInInitializerError
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1006)
	... 33 more
Caused by: java.lang.NullPointerException
	at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:133)
	at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:66)
	at ***.***.SearchIPAttributionService.<clinit>(SearchIPAttributionService.java:28)
	... 40 more

Resolution process:

1. Check the configuration, read it over and over again, and confirm that there is no problem.

2. I found a lot of information on the Internet, and there are many similar questions. After reading the answers, I still can’t find the key points. I have to continue reading the error code until I see this sentence:

Caused by: java.lang.NullPointerException
	at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:133)
	at ***.***.SearchIPAttributionService.load(SearchIPAttributionService.java:66)
	at ***.***.SearchIPAttributionService.<clinit>(SearchIPAttributionService.java:28)

The problem should be in the code itself, but I remember the code was tested and there was no problem. However, there is no other way but to follow the prompts step by step to find the problem. In the end, the problem really lies in the code. When spring instantiates this class, it first executes the static method. At this time, a class has not been instantiated (check whether it has been annotated), so this null pointer error is reported.