Christoph Engelbert will demonstrate how to use MapReduce in Hazelcast for distributed computing. MapReduce allows processing and transforming large datasets in a distributed fashion, and was popularized by Google. It works by mapping inputs to intermediate key-value pairs, reducing those values based on keys, and allows parallel processing across clusters. Hazelcast is an in-memory data grid that can be used as a distributed computing platform and implements MapReduce to allow distributed processing of large datasets across server clusters.