Cannot find the declaration of element 'beans'

Try this, assuming you're on Spring 3.1:

<beans xmlns="http://www.springframework.org/schema/beans" 
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">

Replace 3.1 on the last line with whatever major Spring version you use. Meaning: there is no 3.1.1 XSD even though there is a Spring version 3.1.1.

Found it on another thread that solved my problem... was using an internet connection less network.

In that case copy the xsd files from the url and place it next to the beans.xml file and change the xsi:schemaLocation as under:

 <beans xmlns="http://www.springframework.org/schema/beans" 
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans 
spring-beans-3.1.xsd">

Add this code ..It helped me

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" 
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xmlns:context="http://www.springframework.org/schema/context" 
         xmlns:aop="http://www.springframework.org/schema/aop" 
         xsi:schemaLocation="
         http://www.springframework.org/schema/beans 
           classpath:/org/springframework/beans/factory/xml/spring-beans-3.0.xsd 
         http://www.springframework.org/schema/context 
         classpath:/org/springframework/context/config/spring-context-3.0.xsd
        http://www.springframework.org/schema/aop 
        classpath:/org/springframework/aop/config/spring-aop-3.0.xsd
         ">      
     </beans>

This error of Cannot find the declaration of element 'beans' but for a whole different reason

It turs out my internet connection was not very reliable, so i decided to check first for this url

http://www.springframework.org/schema/context/spring-context-4.0.xsd

Once I saw that the xsd was open succesfully I clean the Eclipse(IDE) project and the error was gone

If you try this steps and still get the error then check the Spring version so that it matches as mentioned by another answer

<beans xmlns="http://www.springframework.org/schema/beans" 
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-**[MAYOR.MINOR]**.xsd">

Replace [MAYOR.MINOR] on the last line with whatever major.minor Spring version that you are using

For Spring 4.0 http://www.springframework.org/schema/context/spring-context-4.0.xsd

For Sprint 3.1 http://www.springframework.org/schema/beans spring-beans-3.1.xsd

All the contexts are available here http://www.springframework.org/schema/context/