The code in a finally clause will never
fail to execute, right?
Using System.exit(1); in try block will not allow finally code to
How many messaging models do JMS provide for and what are they?
JMS provide for two messaging models, publish-and-subscribe and
What information is needed to create a TCP Socket?
The Local Systems IP Address and Port Number. And the Remote Systemís
IPAddress and Port Number.
What Class.forName will do while loading drivers?
It is used to create an instance of a driver and register it with the
DriverManager. When you have loaded a driver, it is available for making
a connection with a DBMS.
How to Retrieve Warnings?
SQLWarning objects are a subclass of SQLException that deal with
database access warnings. Warnings do not stop the execution of an
application, as exceptions do; they simply alert the user that something
did not happen as planned. A warning can be reported on a Connection
object, a Statement object (including PreparedStatement and
CallableStatement objects), or a ResultSet object. Each of these classes
has a getWarnings method, which you must invoke in order to see the
first warning reported on the calling object
SQLWarning warning = stmt.getWarnings();
if (warning != null)
while (warning != null)
System.out.println(\"Message: \" + warning.getMessage());
System.out.println(\"SQLState: \" + warning.getSQLState());
System.out.print(\"Vendor error code: \");
warning = warning.getNextWarning();
How many JSP scripting elements are there and what are they?
There are three scripting language elements: declarations, scriptlets,
In the Servlet 2.4 specification SingleThreadModel has been deprecated,
Because it is not practical to have such model. Whether you set
isThreadSafe to true or false, you should take care of concurrent client
requests to the JSP page by synchronizing access to any shared objects
defined at the page level.
What are stored procedures? How is it useful?
A stored procedure is a set of statements/commands which reside in the
database. The stored procedure is pre-compiled and saves the database
the effort of parsing and compiling sql statements every time a query is
run. Each database has its own stored procedure language, usually a
variant of C with a SQL preproceesor. Newer versions of dbís support
writing stored procedures in Java and Perl too. Before the advent of
3-tier/n-tier architecture it was pretty common for stored procs to
implement the business logic( A lot of systems still do it). The biggest
advantage is of course speed. Also certain kind of data manipulations
are not achieved in SQL. Stored procs provide a mechanism to do these
manipulations. Stored procs are also useful when you want to do Batch
updates/exports/houseKeeping kind of stuff on the db. The overhead of a
JDBC Connection may be significant in these cases.
How do I include static files within a JSP page?
Static resources should always be included using the JSP include
directive. This way, the inclusion is performed just once during the
translation phase. Do note that you should always supply a relative URL
for the file attribute. Although you can also include static resources
using the action, this is not advisable as the inclusion is then
performed for each and every request.
Why does JComponent have add() and remove() methods but Component does
because JComponent is a subclass of Container, and can contain other
components and jcomponents. How can I implement a thread-safe JSP page?
- You can make your JSPs thread-safe by having them implement the
SingleThreadModel interface. This is done by adding the directive <%@
page isThreadSafe="false" % > within your JSP page.
How do I prevent the output of my JSP or Servlet pages from being cached
by the browser?
You will need to set the appropriate HTTP header attributes to prevent
the dynamic content output by the JSP page from being cached by the
browser. Just execute the following scriptlet at the beginning of your
JSP pages to prevent them from being cached at the browser. You need
both the statements to take care of some of the older browser versions.
How do you restrict page errors display in the JSP page?
You first set "Errorpage" attribute of PAGE directory to the name of the
error page (ie Errorpage="error.jsp")in your jsp page .Then in the error
jsp page set "isErrorpage=TRUE". When an error occur in your jsp page it
will automatically call the error page.
Page Numbers : 1