Resolve error "org.springframework.beans.factory.BeanCreationException: Error creating bean with name Hello': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: Method must not be null"

I think every Spring beginner will face this issue.Have no clues,Code seems like perfect.Tried all possible ways to resolve it? 

see below!

Reason: Its because of using different versions of the spring jars in the project.

Resolution:

 Clean the libraries/jars added to the project.Remove all the libraries from the class path.Then add the libraries into the project from the same version of Spring.

You can find the libraries in the Spring website  

http://www.springsource.org/download

Make sure that all the libraries added in the project are from the same spring version/release.

Stacktrace:

Nested in org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0': Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: Method must not be null:
java.lang.IllegalArgumentException: Method must not be null
    at org.springframework.util.Assert.notNull(Assert.java:112)
    at org.springframework.core.BridgeMethodResolver.findBridgedMethod(BridgeMethodResolver.java:63)
    at org.springframework.beans.GenericTypeAwarePropertyDescriptor.<init>(GenericTypeAwarePropertyDescriptor.java:58)
    at org.springframework.beans.CachedIntrospectionResults.<init>(CachedIntrospectionResults.java:250)
    at org.springframework.beans.CachedIntrospectionResults.forClass(CachedIntrospectionResults.java:144)
    at org.springframework.beans.BeanWrapperImpl.getCachedIntrospectionResults(BeanWrapperImpl.java:252)
    at org.springframework.beans.BeanWrapperImpl.getPropertyDescriptorInternal(BeanWrapperImpl.java:282)
    at org.springframework.beans.BeanWrapperImpl.isWritableProperty(BeanWrapperImpl.java:333)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1247)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1010)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:472)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:515)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:362)
    at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)
   

Resolve Error "org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions INFO: Loading XML bean definitions from class path resource [Beans.xml]"

Spring projects will compile without any warnings and errors.But when you run the code you will see the exception.

 Reason:  It is the issue with the location of the Beans.xml.So server could not find the  location of the Spring beans xml.

Stacktrace :org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [Beans.xml]
org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from class path resource [Beans.xml]; nested exception is java.io.FileNotFoundException: class path resource [Beans.xml] cannot be opened because it does not exist
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:349)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:310)
    at org.springframework.beans.factory.xml.XmlBeanFactory.<init>(XmlBeanFactory.java:73)
    at org.springframework.beans.factory.xml.XmlBeanFactory.<init>(XmlBeanFactory.java:61)
    at com.mySpringExample.helloExample.HelloClient.main(HelloClient.java:20)
Caused by: java.io.FileNotFoundException: class path resource [Beans.xml] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:143)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:336)
    ... 4 more

Resolution :  

1) Move the spring Beans.xml to the src folder from the current folder. 

Clean and run the project.

See the screen shots below.

Wrong location(Example)

Right location