package in.bench.resources.collection;

import java.util.LinkedHashSet;
import java.util.Set;

public class UpperCaseDuplicateCharacterInString {

	public static void main(String[] args) {

		// sample test string
		String testStr = "madam sss gg fff rr malayalam";
		Set<Character> lhSet = null;

		// Step 1: create StringBuilder object
		// to store converted strings
		StringBuilder sbuilder = new StringBuilder();

		// Step 2: first, LOWER-CASE entire String before any operation
		String lowerStr = testStr.toLowerCase();

		// Step 3: create String[] using
		// space as delimiter in split() method of String
		String[] strArray = lowerStr.split("\\s");

		// Step 4: Iterate original String after split
		for(int index=0; index < strArray.length; index++) {

			// Step 5: store it in temporary variable
			String temp = strArray[index];

			// Step 6: create LinkedHashSet to check/store duplicate
			lhSet = new LinkedHashSet<Character>();

			// Step 7: convert temp String into character-array
			// using toCharArray() method
			char[] chArray = temp.toCharArray();

			// Step 8: iterate through converted char[] array
			for(char ch : chArray) {

				// Step 9: check whether char already present in LHSet
				boolean checkChar = lhSet.contains(ch);

				// Step 10: if not present, then add
				if(!checkChar) {
					lhSet.add(ch);
					sbuilder.append(ch);
				}
				else {
					// Step 11: if present, then store duplicate
					// after converting to UPPER-CASE in StringBuilder
					sbuilder.append(Character.toUpperCase(ch));
				}
			}

			// Step 12: add single space after outer for-loop
			sbuilder.append(" ");
		}

		// Step 13: finally pretty print to console
		System.out.println("Original String  : "
				+ testStr);
		System.out.println("\nConverted String : "
				+ sbuilder.toString().trim());
	}
}

Original String  : madam sss gg fff rr malayalam

Converted String : madAM sSS gG fFF rR malAyALAM