== API ==
You can use the ZooKeeper from within your application via APIs - application programming interface.
Though ZooKeeper provides the core APIs in Java and C, there are contributed libraries in Perl, Python, REST. == sync == For each function of APIs, synchronous and asynchronous both variants are available.
While using synchronous APIs the caller or client will wait till ZooKeeper finishes an operation. But if you are using asynchronous API, the client provides a handle to the function that would be called once zooKeeper finishes the operation.