How to find subsets of a given string

import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class SubstringsWithoutUsingMethod {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Set<String> finalSubsetStrs = new HashSet<String>  ();
		Scanner inpStr=new Scanner (System.in);
		System.out.println("Enter an input word for which you need all the sub sets of strings");
		String inpWord=inpStr.next();
		int sizeOfSubstr=1,beginIdx=0, endIdx=1;

		//Iterate the loop until the substring's length is equals with length of the actual string
		while (sizeOfSubstr <= inpWord.length()) {

	        //Iterate the substring sized loop until the subscript less than or equals the actual length
			while (beginIdx < inpWord.length() && endIdx <= inpWord.length()) 
				finalSubsetStrs.add(prepSubstr(beginIdx++, endIdx++,inpWord));

			sizeOfSubstr++; // Increment size of sub string for the next iteration
			beginIdx=0;
			endIdx=sizeOfSubstr;
		}
		System.out.println("All the unique substrings from the given String="+inpWord+" are below");
		System.out.println(finalSubsetStrs);
		inpStr.close();
	}

	//Function to form the subStrings using StringBuilder Mutable class object
	private static String prepSubstr(int bIdx, int eIdx, String inpWord) {

		StringBuilder formStr=new StringBuilder ();
		for(int i=bIdx;i<=eIdx-1;i++ )
			formStr.append(inpWord.charAt(i));
		return formStr.toString();
	}
}