Should ResultSet be closed?
You should explicitly close Statements , ResultSets , and Connections when you no longer need them, unless you declare them in a try -with-resources statement (available in JDK 7 and after). Connections to Derby are resources external to an application, and the garbage collector will not close them automatically.
Can we use ResultSet after closing connection?
In your code you closed the ResultSet and the Connection , after which the ResultSet is no longer usable. If you want it to be usable you must leave it (and the Connection ) open. However, if you return the ResultSet , you should refactor your code so the calling method provides the Connection .
How do I know if a ResultSet is closed?
The isClosed() method of the ResultSet interface is used to determine whether the current ResultSet object is closed.
Why is ResultSet empty?
The JDBC ResultSet doesn’t provide any isEmpty(), length() or size() method to check if its empty or not. Hence, when a Java programmer needs to determine if ResultSet is empty or not, it just calls the next() method and if next() returns false it means ResultSet is empty.
What happens when ResultSet is closed?
A ResultSet object is automatically closed when the Statement object that generated it is closed, re-executed, or used to retrieve the next result from a sequence of multiple results. The number, types and properties of a ResultSet object’s columns are provided by the ResultSetMetaData object returned by the ResultSet.
Should I close ResultSet and PreparedStatement?
You should explicitly close your Statement and PreparedStatement objects to be sure. ResultSet objects might also be an issue, but as they are guaranteed to be closed when the corresponding Statement/PreparedStatement object is closed, you can usually disregard it.
Which of the following is the correct order to close the database object?
Explanation: When manually closing database resources, they should be closed in the reverse order from which they were opened. This means that the ResultSet object is closed before the Statement object and the Statement object is closed before the Connection object.
What does ResultSet closed mean?
Can ResultSet be null in Java?
No matter how many rows are returned(starting from 0), the resultSet will never be null. The only case in which a resultset will remain null is when an exception is thrown… but the program flow will jump to the Exception handling block anyways.
What does ResultSet next return?
This method returns a boolean value specifying whether the ResultSet object contains more rows. If there are no rows next to its current position this method returns false, else it returns true.
Does closing connection close PreparedStatement?
Resultset, preparedstatement, statement all are created from connection. If you have closed the connection, automatically all above will be closed as parent is not available.
How to close a resultset that is already open?
Well, your method opens a ResultSet by executing the query. When you execute a statement, any ResultSet that is already open, is closed again. So, by using a recursive method in this manner, by the time you come to the r.next in the “previous” method the ResultSet has already been closed.
Why do I get resultsetclosedexception?
A ResultSetClosedException could be thrown for two reasons. 1.) You have opened another connection to the database without closing all other connections. 2.) Your ResultSet may be returning no values. So when you try to access data from the ResultSet java will throw a ResultSetClosedException. Thanks for contributing an answer to Stack Overflow!
How many resultset objects can be open at the same time?
By default, only one ResultSet object per Statement object can be open at the same time. Therefore, if the reading of one ResultSet object is interleaved with the reading of another, each must have been generated by different Statement objects.
Why I am not using stored procedures?
I am not using stored procedures because there are some restrictions. Sql statements can also be passed as parameters. This discussion has been closed.