Data structures usefull links

http://www.careerride.com/Data-Structure-Interview-Questions.aspx

http://www.dsalgo.com/

http://uniqueminds.in/Thread-Data-Structures-and-Algorithm-Interview-Questions-for-Java-Programmers

http://www.idevelopment.info/data/Programming/data_structures/overview/Data_Structures_Algorithms_Introduction.shtml

http://www.javaworld.com/article/2073390/core-java/datastructures-and-algorithms--part-1.html

how to know the constraints on table in oracle..............

select * from user_cons_columns ucc, user_constraints uc 

where uc.constraint_name=ucc.constraint_name

and uc.constraint_type='P' and uc.table_name = 'Table Name';

R = Referential Constraint/Foreign Key constraint

C = Check Constraint

P = Primary Key

U = Unique Key

(or)

select 

   cons.owner            as child_owner, 

   cons.table_name       as child_table,

   cons.constraint_name     constaint_name,

   cons.constraint_type     constraint_type,

   col.owner                parent_owner, 

   col.table_name           parent_table,

   col.column_name          column_name

from dba_cons_columns      col, 

     dba_constraints       cons

where 

   cons.r_owner = col.owner

and 

   cons.r_constraint_name = col.constraint_name

and 

   cons.table_name = 'Table Name';

   

(or)

   select * 

from

    all_constraints 

where

    r_constraint_name in

    (select       constraint_name

    from

       all_constraints

    where

       table_name='Table Name') 

Debugging techniques in Eclipse............

http://eclipsesource.com/blogs/2013/01/08/effective-java-debugging-with-eclipse/
http://www.vogella.com/articles/EclipseDebugging/article.html

Java API- Implementations

Please refer the below site for the java open source  API & its implementations.
http://java-source.net/
http://freecode.com/tags/java-libraries
http://www.jdocs.com/page/AllLibraries
http://www.theserverside.com/

how to find 2nd highest salary or 2nd lowest salary?

second highest
SELECT

* FROM employee e1
WHERE

2 = (SELECT COUNT(DISTINCT (e2.Emp_Salary))FROM emp e2 WHERE e2.Emp_Salary >= e1.Emp_Salary)
second lowest
SELECT * FROM employee e1
WHERE

2 = (SELECT COUNT(DISTINCT (e2.Emp_Salary))FROM emp e2 WHERE e2.Emp_Salary <= e1.Emp_Salary)

SELECT salary FROM TN a 
    WHERE n - 1 = (SELECT COUNT(salary) FROM TN b WHERE b.salary > a.salary)

oracle

..........

select max(sal) from emp where sal not in (select max(sal) from emp)

Datasource configuration for DB2 in Jboss 7.1

 <datasource jta="true" jndi-name="java:jboss/datasources/DataSource" pool-name="DataSource" enabled="true" use-java-context="true" use-ccm="true">
                    <connection-url>url</connection-url>
                    <driver>db2jdbc</driver>
                    <pool>
                        <min-pool-size>10</min-pool-size>
                        <max-pool-size>100</max-pool-size>
                        <prefill>true</prefill>
                    </pool>
                    <security>
                        <user-name>user</user-name>
                        <password>pw</password>
                    </security>
                </datasource>
                <drivers>
                 
                    <driver name="db2jdbc" module="com.ibm.db2">
                        <driver-class>com.ibm.db2.jcc.DB2Driver</driver-class>
                        <xa-datasource-class>com.ibm.db2.jcc.DB2XADataSource</xa-datasource-class>
                    </driver>
 </drivers>


Create Folder Structure:jboss-as-7.1.1.Final\modules\com\ibm\db2\main
place Module,xml file and related jar files
<module xmlns="urn:jboss:module:1.1" name="com.ibm.db2">
<resources>
<resource-root path="db2jcc.jar"/>
<resource-root path="db2jcc_license_cu.jar"/>
</resources>
<dependencies>
<module name="javax.api"/>
<module name="javax.transaction.api"/>
<module name="javax.servlet.api" optional="true"/>
</dependencies>
</module>


and invoke from java code
..................................

InitialContext context = new InitialContext();
 DataSource dataSource = (DataSource) context.lookup("java:jboss/datasources/SampleDS");
Connection connection = dataSource.getConnection();

Default radio button & Dropdown values selected using spring mvc in jsp

<form:radiobutton path="rBusiness"

value='rnmName' id="rnmName" checked="checked"/>

<

form:select path="recordsPerPage" >

<form:option value="10" label="10"/>

<form:option value="15" label="15"/>

<form:option value="20" label="20"/>

<form:option value="25" label="25" selected="selected"/>

<form:option value="30" label="30"/>

<form:option value="40" label="40"/>

<form:option value="50" label="50" /></form:select>