[SalesForce] Cache.Session return null value

I have create small function to store and retrieve the value inside static using session cache. but i am unable to get the data which i have stored in session cache. I am not getting any error on retrieve or inserting but Always return null value. Any one can help me.

Here is My platform Cache setting

Apex Controller :

public class SessionCacheController {
    public  static String name {get;set;}
    public  static String check {get;set;}
    public  static String dummy {get;set;}
    private static final String KEY = 'Key';
    private static final String VALUE = 'Any value';

    //adding key,value pair to cache 
    public static void  setData()
    {      
        dummy='setData';
        Cache.Session.put('MyPackagePrefix.PlatformCache.myName', 'Nithesh K');             

        Cache.Partition partition = Cache.Session.getPartition('PlatformCache');
        partition.put(KEY, VALUE);                     
    }

    //retrieve value by key 
    public static void getData()
    {
        dummy='getData';
        Name=(String)Cache.Session.get('MyPackagePrefix.PlatformCache.myName');   
        system.debug('myName *** ' + Name); // return null

        Cache.Partition partition = Cache.Session.getPartition('PlatformCache');
        check = (String) partition.get(KEY);
        system.debug('check *** ' +  check); // return null
    }
}

Visual force Page

 <apex:page controller="SessionCacheController">
    <apex:form >
    <apex:pageBlock id="pageSection">
        <apex:outputText >  My name {! Name  } </apex:outputText>   <br/>   
         <apex:outputText > Check Key {! check  } </apex:outputText>   <br/> 
         <apex:outputText > dummy {! dummy  } </apex:outputText>   <br/> 
    </apex:pageBlock>

    <apex:commandButton value="setData" action="{!setData }" reRender="pageSection"/>
    <apex:commandButton value="getData" action="{!getData }" reRender="pageSection"/>
    </apex:form>

</apex:page>

When i click setData() command-button, Value is added cache.session and getData() value is retrieve from cache.session and render in visual force page .