default boolean isKeySecret() {
        return this.secretKey.get();
    }
Returns an existing {@link Lock} on the specified key or creates a new one
if none was found. This operation is thread safe. Successive calls with the same key may or may not
return the same {@link Lock}. However, different threads asking for the
same Lock at the same time will get the same Lock object.

<p>The supplied cache may or may not be used depending whether the server is running on cluster mode
or not. When not running as part of a cluster then the lock will be unrelated to the cache and will
only be visible in this JVM.

@param key the object that defines the visibility or scope of the lock.
@return an existing lock on the specified key or creates a new one if none was found.
xmppserver/src/main/java/org/jivesoftware/util/cache/Cache.java