#vulnerable code 
                              @Override
  public void init() throws DBException {
    if ("true"
        .equals(getProperties().getProperty("clientbuffering", "false"))) {
      this.clientSideBuffering = true;
    }
    if (getProperties().containsKey("writebuffersize")) {
      writeBufferSize =
          Long.parseLong(getProperties().getProperty("writebuffersize"));
    }

    if (getProperties().getProperty("durability") != null) {
      this.durability =
          Durability.valueOf(getProperties().getProperty("durability"));
    }

    if ("kerberos".equalsIgnoreCase(config.get("hbase.security.authentication"))) {
      config.set("hadoop.security.authentication", "Kerberos");
      UserGroupInformation.setConfiguration(config);
    }

    if ((getProperties().getProperty("principal")!=null) 
        && (getProperties().getProperty("keytab")!=null)) {
      try {
        UserGroupInformation.loginUserFromKeytab(getProperties().getProperty("principal"), 
              getProperties().getProperty("keytab"));
      } catch (IOException e) {
        System.err.println("Keytab file is not readable or not found");
        throw new DBException(e);
      }
    }

    try {
      synchronized(threadCount) {
        ++threadCount;
        if (connection == null) {
          connection = ConnectionFactory.createConnection(config);
        }
      }
    } catch (java.io.IOException e) {
      throw new DBException(e);
    }

    if ((getProperties().getProperty("debug") != null)
        && (getProperties().getProperty("debug").compareTo("true") == 0)) {
      debug = true;
    }

    if ("false"
        .equals(getProperties().getProperty("hbase.usepagefilter", "true"))) {
      usePageFilter = false;
    }

    columnFamily = getProperties().getProperty("columnfamily");
    if (columnFamily == null) {
      System.err.println("Error, must specify a columnfamily for HBase table");
      throw new DBException("No columnfamily specified");
    }
    columnFamilyBytes = Bytes.toBytes(columnFamily);

    // Terminate right now if table does not exist, since the client
    // will not propagate this error upstream once the workload
    // starts.
    String table = com.yahoo.ycsb.workloads.CoreWorkload.table;
    try {
      final TableName tName = TableName.valueOf(table);
      connection.getTable(tName).getTableDescriptor();
    } catch (IOException e) {
      throw new DBException(e);
    }
  } 
                            #location 34 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                              @Override
  public void init() throws DBException {
    if ("true"
        .equals(getProperties().getProperty("clientbuffering", "false"))) {
      this.clientSideBuffering = true;
    }
    if (getProperties().containsKey("writebuffersize")) {
      writeBufferSize =
          Long.parseLong(getProperties().getProperty("writebuffersize"));
    }

    if (getProperties().getProperty("durability") != null) {
      this.durability =
          Durability.valueOf(getProperties().getProperty("durability"));
    }

    if ("kerberos".equalsIgnoreCase(config.get("hbase.security.authentication"))) {
      config.set("hadoop.security.authentication", "Kerberos");
      UserGroupInformation.setConfiguration(config);
    }

    if ((getProperties().getProperty("principal")!=null)
        && (getProperties().getProperty("keytab")!=null)) {
      try {
        UserGroupInformation.loginUserFromKeytab(getProperties().getProperty("principal"),
              getProperties().getProperty("keytab"));
      } catch (IOException e) {
        System.err.println("Keytab file is not readable or not found");
        throw new DBException(e);
      }
    }

    try {
      threadCount.getAndIncrement();
      synchronized (CONNECTION_LOCK) {
        if (connection == null) {
          // Initialize if not set up already.
          connection = ConnectionFactory.createConnection(config);
        }
      }
    } catch (java.io.IOException e) {
      throw new DBException(e);
    }

    if ((getProperties().getProperty("debug") != null)
        && (getProperties().getProperty("debug").compareTo("true") == 0)) {
      debug = true;
    }

    if ("false"
        .equals(getProperties().getProperty("hbase.usepagefilter", "true"))) {
      usePageFilter = false;
    }

    columnFamily = getProperties().getProperty("columnfamily");
    if (columnFamily == null) {
      System.err.println("Error, must specify a columnfamily for HBase table");
      throw new DBException("No columnfamily specified");
    }
    columnFamilyBytes = Bytes.toBytes(columnFamily);

    // Terminate right now if table does not exist, since the client
    // will not propagate this error upstream once the workload
    // starts.
    String table = com.yahoo.ycsb.workloads.CoreWorkload.table;
    try {
      final TableName tName = TableName.valueOf(table);
      synchronized (CONNECTION_LOCK) {
        connection.getTable(tName).getTableDescriptor();
      }
    } catch (IOException e) {
      throw new DBException(e);
    }
  }