Add one story with 6 scenarios and steps for CreditCardValidator.
Add unit test cases for CreditCardValidator.
Add ValidationException for wrapping the exception coming from all of
the validators.
Add one class to store the common symbols using in the project.
Add 3 error codes and error messages covered the user fault as below:
"invalid char", "invalid format", "
Finish the comments(Because of press wrong button by accident in
previous commit)
Add 3 error codes and error messages covered the user fault as below:
"invalid char", "invalid format", "invalid number"

And make ErrorMessage as abstract since no need to create an instance
for this kind of class.
Update SymbolPool as abstract since no need to create instance for this
class. 
Add final for all the fields to make them be constants.
Add one field: emtpy=""
Add "[" and "]" symbols in the SymbolPool
Update the incorrect inputs in the unit test cases
Add CreditCardValidator.afterPropertiesSet() in the
CreditCardValidatorCheckSteps java file.
Update the incorrect input in the story file
Add the root interface of validators
Create a util class for algorithm.
Add spring core and beans v4.0.5.RELEASE as compile dependencies
Add spring application.context.xml file to manage the lifecycle of beans
Implement the credit card number validation.
Add commons-lang v2.5 in compile due to fix the issue
"org.apache.commons.lang package not existing"
Create a variable for StringUtils.join() to avaid to cause other issue
because of "org.apache.commons.lang package not exising"
Add unit test cases for AlgorithmUtils.