MapR-DB supports all of the Apache HBase 0.98 Java APIs, except where noted in this documentation. For a number of critical Java APIs, for filters, and for comparators, this documentation explicitly lists what is supported, rather than what is not supported.
Code written for Apache HBase can be easily ported to use MapR-DB tables.
MapR-DB tables do not support low-level HBase API calls that are used to manipulate the state of an Apache HBase cluster. HBase API calls that are not supported by MapR-DB tables report successful completion to allow legacy code written for Apache HBase to continue executing, but do not perform any actual operations.