@Override
  protected void deserializeStateData(ProcedureStateSerializer serializer) throws IOException {
    super.deserializeStateData(serializer);

    MasterProcedureProtos.CreateNamespaceStateData createNamespaceMsg =
      serializer.deserialize(MasterProcedureProtos.CreateNamespaceStateData.class);
    nsDescriptor = ProtobufUtil.toNamespaceDescriptor(createNamespaceMsg.getNamespaceDescriptor());
  }
The procedure to create a new namespace.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/CreateNamespaceProcedure.java