Google Memcache With Java

[Ecd via StackOverflow]

Could you please help me for using Google Memcache Service with Java ? Maybe there is an authentication problem? Is that? How can i authenticate with p12 file?

MemcacheService syncCache = MemcacheServiceFactory.getMemcacheService("mycache");
              value = (byte[]) syncCache.get(key); // Read from cache.
              if (value == null) {
                // Get value from another source.
                // ........

                syncCache.put(key, value); // Populate cache.
              }

I am getting this error :

com.google.apphosting.api.ApiProxy$CallNotFoundException: The API package 'memcache' or call 'Get()' was not found.
    at com.google.apphosting.api.ApiProxy$1.get(ApiProxy.java:173)
    at com.google.apphosting.api.ApiProxy$1.get(ApiProxy.java:171)
    at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:88)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.quietGet(MemcacheServiceImpl.java:26)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.get(MemcacheServiceImpl.java:49)

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