jdbc-protolib/src/main/java/com/streamsets/pipeline/lib/jdbc/multithread/ConnectionManager.java
public Connection getConnection() throws SQLException {
    if (threadLocalConnection.get() == null) {
      threadLocalConnection.set(getNewConnection());
    }
    return threadLocalConnection.get();
  }
public Connection getConnection() throws SQLException {
    if (threadLocalConnection.get() == null) {
      threadLocalConnection.set(getNewConnection());
    }
    return threadLocalConnection.get();
  }
Get {@link Connection} if cached connection is null fetch a connection from {@link HikariDataSource}
@return {@link Connection}
@throws SQLException