Statement executeQuery(String query) is used to execute Select queries and returns the ResultSet. ResultSet returned is never null even if there are no records matching the query. When executing select queries we should use executeQuery method so that if someone tries to execute insert/update statement it will throw java.sql.SQLException with message “executeQuery method can not be used for update”.
Core Java is something that provides the API's like regular expression, String handling, collections. But enterprise java involves writing scalable, secure and per-formant applications which can have large user base.
Batch processing helps you to group related SQL statements into a batch and execute them instead of executing a single query. By using batch processing technique in JDBC, you can execute multiple queries which makes the performance faster.
response.setHeader (“Expires”, “0”); //prevents caching at the proxy server
The ResultSet object represents a row of a table. It can be used to change the cursor pointer and get the information from the database.
This method returns an array containing each element on the stack trace. The element at index 0 represents the top of the call stack whereas the last element in the array represents the method at the bottom of the call stack.
The Connection interface maintains a session with the database. It can be used for transaction management. It provides factory methods that returns the instance of Statement, PreparedStatement, CallableStatement and DatabaseMetaData.
Finally block is a block which always executes a set of statements. It is always associated with a try block regardless of any exception that occurs or not.
Yes, finally will not be executed if the program exits either by calling System.exit() or by causing a fatal error that causes the process to abort.
Jquery and DOJO are java script frameworks for writing rich web applications but AJAX is a server communication mechanism which can issue requests without page reload.