public static HadoopThriftAuthBridge getBridge() {
    if (self == null) {
      synchronized (HadoopThriftAuthBridge.class) {
        if (self == null) self = new HadoopThriftAuthBridge23();
      }
    }
    return self;
  }
Functions that bridge Thrift's SASL transports to Hadoop's
SASL callback handlers and authentication classes.
HIVE-11378 This class is not directly used anymore.  It now exists only as a shell to be
extended by HadoopThriftAuthBridge23 in 0.23 shims.  I have made it abstract
to avoid maintenance errors.
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/security/HadoopThriftAuthBridge.java