code: protected JdbcProvider createJdbcSource() {
      String driver = this.workUnitState.getProp(ConfigurationKeys.SOURCE_CONN_DRIVER);
      String userName = this.workUnitState.getProp(ConfigurationKeys.SOURCE_CONN_USERNAME);
      String password = PasswordManager.getInstance(this.workUnitState)
          .readPassword(this.workUnitState.getProp(ConfigurationKeys.SOURCE_CONN_PASSWORD));
      String connectionUrl = this.getConnectionUrl();
  
      String proxyHost = this.workUnitState.getProp(ConfigurationKeys.SOURCE_CONN_USE_PROXY_URL);
      int proxyPort = this.workUnitState.getProp(ConfigurationKeys.SOURCE_CONN_USE_PROXY_PORT) != null
          ? this.workUnitState.getPropAsInt(ConfigurationKeys.SOURCE_CONN_USE_PROXY_PORT) : -1;
  
      if (this.jdbcSource == null || this.jdbcSource.isClosed()) {
        this.jdbcSource = new JdbcProvider(driver, connectionUrl, userName, password, 1, this.getTimeOut(), "DEFAULT",
            proxyHost, proxyPort);
        return this.jdbcSource;
      } else {
        return this.jdbcSource;
      }
    }
docs: Create JDBC source to get connection
  
  @return JDBCSource