MySQL NDB Cluster Connector for Java, also known as ClusterJ, is a Java API for writing applications against NDB Cluster. It is one among different access paths and styles of access to NDB Cluster data. Section 4.1.2, “Java and NDB Cluster”, describes each of those APIs in more detail.
MySQL NDB Cluster Connector for Java is included with all NDB Cluster source and binary releases. Building MySQL NDB Cluster Connector for Java from source can be done as part of building NDB Cluster; however, it can also be built with Maven.