Protected vs. Private methods in Java

Unless you have a specific reason to make the method private - like you expressly want to prevent subclasses from accessing the method - methods should be protected. This way we can subclass this tag.

if/else vs. switch

When writing code that branches on enum values, instead of if/else blocks, use the switch statement like so:

    switch (selectedTab) {
    case (Tab.SITES):
        //do something for sites
    case (Tab.CATEGORY):
        //do something for category
    case (Tab.DEMOGRAPHIC):
        //do something for demographics    
    case (Tab.ALL_SITES):
        //do something for all sites
    }

Lengthy and nested methods: Methods should small, atomic and easy to read. Break it up like so:

    switch (selectedTab) {
    case (Tab.SITES):
        renderSitesTab();
    case (Tab.CATEGORY):
        renderCategoryTab();
    case (Tab.DEMOGRAPHIC):
        renderDemographicsTab();
    case (Tab.ALL_SITES):
        renderAllSites();
    }

Comparison in Enums

Tip on Enums

Instead of using id to do equality comparisons for enums, use the enum itself.

Example: Instead of
if (selectedTab.getId() == Tab.SITES.getId()) {
use:
if (selectedTab.equals(Tab.SITES)) {

StringBuilder vs. StringBuffer

A tip on StringBuilder vs. StringBuffer

• We should be using StringBuilder over StringBuffer. It’s a drop-in replacement, all the method names and arguments are the same.


• StringBuilder is not synchronized and therefore doesn’t require object locks everytime a method is called. The only time we’d use StringBuffer is when it’s a member variable with a possibility of multiple threads writing to it.

Check the version of applications running on Linux

OS version: uname -a cat /etc/redhat-release Apache version: httpd -v /usr/local/apache/bin/httpd -version Jrun version For JRun 3.0, look at logs /opt/jrun/bin/jrun -version Perl /usr/sbin/perl -version (-v works too) Sendmail /usr/lib/sendmail -d0.1 -bt cat /proc/version

Problem with date format in JDBC session

The other day I came across this issue and spent some time figuring out what was going on. Hope it can help someone.

Issue:
Say there’s a stored procedure in Oracle named test_date which uses a variable of type DATE. The variable is not returned to java but simply used elsewhere in the procedure.
If I execute this procedure in oracle and check the date format, I see it’s using the format dd-mon-yyyy

If I execute this procedure over jdbc, the format I see is mm-dd-yyyy

This makes me believe that the date format used throughout the session is defined by the client (oracle vs. jdbc).

Fix:
Simple way to fix this is to alter the session at runtime and explicitly define the format used throughout the session
alter session set nls_date_format=''DD-MON-YYYY''

Good coding practices I use

1. Write flexible code that can be changed and extended, changes in underlying technologies shouldn't ripple through the whole system


2. Code should be maintainability – long shelf life


3. Layers should not be tightly coupled. Each layer needs to be independent from the other. Use interfaces, dependency injection etc


4. Indent all files using spaces (Indent once = 4 spaces)


5. If you are using an IDE, use the formatter and tools that comes with it to organize and clean up your code


6. Comment your code often. Use Javadoc standards.


7. Use sensible naming conventions for variable, method and class names.


8. Use exceptions only if required. Do not use exceptions to handle errors. If errors occur we want the message to propagated up the call stack.


9. Do not use scriplets in your JSP code. Use JSTL Expression Languages where required.


10. All jsp file names should be in lowercase


11. All text in JSP's should either come from Database or Resource bundles. No text should be hard coded in HTML


12. HTML pages should be XHTML Transitional


13. Validate your HTML pages using w3c validators


14. All styles should be written in css. No HTML style attributes


15. If your code causes warnings or errors in other code, fix other code as well. There shouldn't be any code in CVS which has errors or warnings.