public NamespaceDescriptor build() {
      if (this.bName == null) {
        throw new IllegalArgumentException("A name has to be specified in a namespace.");
      }

      NamespaceDescriptor desc = new NamespaceDescriptor(this.bName);
      desc.configuration = this.bConfiguration;
      return desc;
    }
Remove a config setting represented by the key from the {@link #configuration} map
hbase-common/src/main/java/org/apache/hadoop/hbase/NamespaceDescriptor.java