Some Java Programming Interview Questions

I am going to add some Java programming questions that I have come across in interviews recently. I have tried to provide solutions but of course there might be better ways to do them...

Check if given string contains a valid FID number. If it is not valid, return "invalid". If it is valid, convert the string to one of two formats depending on the input valid of EntityType:

i) If the EntityType value is P (Personal), convert the string to "XXX-XX-XXXX" format.

ii) If the EntityType value is B (Business), convert the string to "XX-XXXXXXX" format.

You can assume the EntityType is set correctly to either P or B.

Valid input formats when EntityType = P are: 123-44-9876, 123449876, 123 44 9876

If the user inputs any other format than the above 3, the program should return Invalid entry. For example, 123-44 9876 is invalid.

Valid input formats when EntityType = B are: 98-1234567, 981234567, 98 1234567, 981-23-4567

Examples

222-44-9876 and EntityType=P -> 222-44-9876

222-44-9876 and EntityType=B -> 22-2449876

package com.programming.interview;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class FIDChecker {

public static String checkFID(String strFID, String entityType ){

String returnFID = "INVALID FID/ENTITY TYPE";

entityType = ("P".equalsIgnoreCase(entityType)||"B".equalsIgnoreCase(entityType))? entityType:null;

if(null!=strFID && null!= entityType)

{

if (validateFID(strFID, entityType))

{

returnFID = reformatFID(strFID, entityType);

}

}

return returnFID;

}

private static boolean validateFID(String strFID, String entityType){

boolean isValidFID = false;

String validFormat1 = null;

String validFormat2 = null;

if ("P".equalsIgnoreCase(entityType))

{

validFormat1 = "\\d{3}-?\\d{2}-?\\d{4}";

validFormat2 = "\\d{3}\\s?\\d{2}\\s?\\d{4}";

}

else if ("B".equalsIgnoreCase(entityType))

{

validFormat1 = "\\d{2}-?\\d{7}";

validFormat2 = "\\d{2}\\s?\\d{7}";

}

Pattern matchingPattern1 = Pattern.compile(validFormat1);

Matcher patternMatcher1 = matchingPattern1.matcher(strFID);

Pattern matchingPattern2 = Pattern.compile(validFormat2);

Matcher patternMatcher2 = matchingPattern2.matcher(strFID);

if (patternMatcher1.matches() || patternMatcher2.matches())

{

isValidFID = true;

}

return isValidFID;

}

private static String reformatFID(String strFID, String entityType){

String plainFID = strFID.replaceAll("[-\\s]", "");

StringBuffer formattedFID = new StringBuffer();

if("P".equalsIgnoreCase(entityType))

{

formattedFID.append(plainFID.substring(0, 3));

formattedFID.append("-");

formattedFID.append(plainFID.substring(3, 5));

formattedFID.append("-");

formattedFID.append(plainFID.substring(5, 9));

}

else if ("B".equalsIgnoreCase(entityType))

{

formattedFID.append(plainFID.substring(0, 2));

formattedFID.append("-");

formattedFID.append(plainFID.substring(2, 9));

}

return formattedFID.toString();

}

}