If you're just including raw HTML, use the #include directive as usual inside your .jsp file.
<!--#include file="data.inc"-->
But it's a little trickier if you want the server to evaluate any JSP code that's inside the included file. If your data.inc file contains jsp code you will have to use <%@ vinclude="data.inc" %> The <!--#include file="data.inc"--> is used for including non-JSP files.

  Using the #define method of declaring a constant enables you to declare a constant in one place and use it throughout your program. This helps make your programs more maintainable, because you need to maintain only the #define statement and not several instances of individual constants throughout your program.
For instance, if your program used the value of pi (approximately 3.14159) several times, you might want to declare a constant for pi as follows:
  #define PI 3.14159
Using the #define method of declaring a constant is probably the most familiar way of declaring constants to traditional C programmers. Besides being the most common method of declaring constants, it also takes up the least memory. Constants defined in this manner are simply placed directly into your source code, with no variable space allocated in memory. Unfortunately, this is one reason why most debuggers cannot inspect constants created using the #define method.

 Static resources should always be included using the JSP include directive. This way, the inclusion is performed just once during the translation phase. The following example shows the syntax: 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.

 Maping parameter represents a constant value that U can define before running a session.A mapping parameter retains the same value throughout the entire session.
When u use the maping parameter ,U declare and use the parameter in a maping or maplet.Then define the value of parameter in a parameter file for the session.
Unlike a mapping parameter,a maping variable represents a value that can change throughout the session.The informatica server saves the value of maping variable to the repository at the end of session run and uses that value next time U run the session.
  Mapping variables have two identities:
  Start value and Current value
  Start value = Current value ( when the session starts the execution of the undelying mapping)
  Start value <> Current value ( while the session is in progress and the variable value changes in one ore more occasions)
  Current value at the end of the session is nothing but the start value for the subsequent run of the same session.

 The preprocessor will include whatever file you specify in your #include statement. Therefore, if you have the line
 #include
In your program, the file macros.inc will be included in your precompiled program. It is, however, unusual programming practice to put any file that does not have a .h or .hpp extension in an #include statement. You should always put a .h extension on any of your C files you are going to include. This method makes it easier for you and others to identify which files are being used for preprocessing purposes. For instance, someone modifying or debugging your program might not know to look at the macros.inc file for macro definitions. That person might try in vain by searching all files with .h extensions and come up empty. If your file had been named macros.h, the search would have included the macros.h file, and the searcher would have been able to see what macros you defined in it.

 Parameter file is to define the values for parameters and variables used in a session.A parameter file is a file created by text editor such as word pad or notepad.
U can define the following values in parameter file
 Maping parameters
 Maping variables
 session parameters

Mapping parameter represents a constant value defined before mapping run.
  Mapping reusability can be achieved by using mapping parameters.
  Mapping variable represents a value that can be changed during the mapping run.
  Mapping variable can be used in incremental loading process.

 Type2 Dimension/Version Data Maping: In this maping the updated dimension in the source will gets inserted in target along with a new version number.And newly added dimension in source will inserted into target with a primary key.
 Type2 Dimension/Flag current Maping: This maping is also used for slowly changing dimensions.In addition it creates a flag value for changed or new dimension. Flag indiactes the dimension is new or newlyupdated.Recent dimensions will gets saved with cuurent flag value 1. And updated dimensions r saved with the value 0.
 Type2 Dimension/Effective Date Range Maping: This is also one flavour of Type2 maping used for slowly changing dimensions.This maping also inserts both new and changed dimensions in to the target.And changes r tracked by the effective date range for each version of each dimension.