How to find subsets of a given strings using Multithreads

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class SubsetsOfGivenStrings {

	public static void main(String[] args) throws InterruptedException {

		List<String> allStrings = new ArrayList<String>();
		allStrings.add("Sowmyanath");
		allStrings.add("Sivani");
		allStrings.add("Rajeshwari");
		allStrings.add("Anjanisurekha");
		allStrings.add("Nagendra");

		List<SubsetThread> threads = new ArrayList<>();

		for (String word : allStrings)
			threads.add(new SubsetThread(1, 0, 1, word));

		for (Thread thread : threads) {
			thread.start();
		}

		// Main thread wait until all the child threads completes.
		for (Thread thread : threads) {
			thread.join();
		}

		for (int i = 0; i < allStrings.size(); i++) {
			SubsetThread subsetThread = threads.get(i);
			if (subsetThread.isFinished()) {
				System.out.println("Subsets of " + allStrings.get(i) + " are " + subsetThread.getAllSubsets());
			} else {
				System.out.println("The calculation of subsets for " + allStrings.get(i) + " is still in progress");
			}
		}
	}

	public static class SubsetThread extends Thread {

		private Set<String> finalSubsetStrs = new HashSet<String>();
		private int sizeOfSubstr;
		private int beginIdx;
		private int endIdx;
		private String inpStr;
		private boolean isFinished;

		// Initialize the constructor begin, end index params.
		// and initialize the substring, and it's size
		SubsetThread(int a, int b, int c, String d) {
			this.sizeOfSubstr = a;
			this.beginIdx = b;
			this.endIdx = c;
			this.inpStr = d;
		}

		// call the subsets routine from the run, and set finished to TRUE
		public void run() {
			this.finalSubsetStrs = Subsets(inpStr);
			isFinished = true;
		}

		public Set<String> Subsets(String inpWord) {
			// 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(inpWord.substring(beginIdx++, endIdx++));

				sizeOfSubstr++; // Increment size of sub string for the next iteration
				beginIdx = 0;
				endIdx = sizeOfSubstr;
			}
			return finalSubsetStrs;
		}

		public boolean isFinished() {
			return isFinished;
		}

		public Set<String> getAllSubsets() {
			return finalSubsetStrs;
		}
	}
}