When I run junit test, encountered this error:　

java.lang.NoClassDefFoundError: 

com/fasterxml/jackson/core/JsonProcessingException

Solution: add the following dependencies:

<dependency>  
            <groupId>com.fasterxml.jackson.core</groupId>  
            <artifactId>jackson-core</artifactId>  
            <version>2.1.0</version>  
        </dependency>  
        <dependency>  
            <groupId>com.fasterxml.jackson.core</groupId>  
            <artifactId>jackson-databind</artifactId>  
            <version>2.1.0</version>  
        </dependency>  
        <dependency>  
            <groupId>com.fasterxml.jackson.core</groupId>  
            <artifactId>jackson-annotations</artifactId>  
            <version>2.1.0</version>  
        </dependency>

Reference:

  1. http://stackoverflow.com/questions/14333709/spring-mvc-3-2-and-json-objectmapper-issue