OracleXMLQuery: Exception when accessing nested tables

Problem When using OracleXMLQuery to access nested tables, generated XML contains error message

oracle.xml.sql.OracleXMLSQLException: getCollectionMetaData:  this method is not supported by ‘OracleXMLDataSetGenJdbc’ class.  Please use ‘OracleXMLDataSetExtJdbc’ instead.

Description when using OracleXMLQuery to query a view which has a column of user defined type (or Table TYPE column), query executed successfully without any exception.

But when the XML string is obtained using

oxq.getXMLString()

XML String contains above error message.

Driver: Oracle JDBC Driver.

Databse: Oracle 10g

Solution: Looking for solution, if you know the solution, please let me know.

I have found that If I use oracle 9I driver (classes12.zip) instead of classes12.jar or ojdbc14.jar, it works. yes it works but I dont know why !

OracleXMLQuery and xml type columns

Problem: OracleXMLQuery escapes xml if the result set has a column which itself contains xml string.

Description: I have a database view with a varchar2 type column. the column contains xml string. when I use OracleXMLQuery to select data from the view, OracleXMLQuery escapes the xml string.

Solution: I am still looking for the solution, I have tried by changing the column type to XML type, but that also didnt work.

Unable to install breakpoint due to missing line number attributes

Unable to install break points in eclipse.
This is a very common error with eclipse. When you try to set a break point, eclipse says “unable to install breakpoint due to missing line number attributes”.

Description of the error

Can not set the break point. A dialog box appears with the error message like

Unable to install breakpoint in xyz class due to missing line number attributes. modify compiler options to generate line number attributes.

Reason: Absent line number attributes in generated class file.

Solution
Follow this steps if you are compiling classes using eclipse

1. If you are compiling using the eclipse. Verify the class file generation options.

Go to windows > preferences > Java > compiler screen.

Make sure that add line number attributes to generated files (used by debugger) check box is checked.

If you don’t know, what other options are. Check all other three check boxes also.

Eclipse - preferences

Follow this steps if you are compiling using ANT

Look into the build file and make sure that debug attribute is set to true in javac task

<javac  debug=”true” srcdir=”" destdir=”">

Set debug=”true” and build again.

<javac srcdir=”"  destdir=”" verbose=”false” debug=”true” debuglevel=”lines,vars,source”>

That’s it !! Try setting the break point again.

What this blog is about?

You may be wondering what this blog is about !!.

This blog is about the errors, problems, configuration issues that I faced when doing my job of a Java programmer.

Here I write about the problems which casued me to open the google and seach atleast for an hour, ask questions on forums, post questions in mailing lists, or take whatever the alternatives are to solve the problem. When the problem is solved finally, I write the solution here so that it can save the time of others.