Java: Check the number of appearances of the two substrings appear anywhere in the string

import java.util.*;

// Define a class named Main
public class Main {
  
  // Method to check the equality of appearances of "the" and "is" in the string
  public boolean isAndTheEquality(String stng) {
    int l = stng.length(); // Get the length of the given string
    int st_the = 0; // Initialize a counter for occurrences of "the"
    int st_is = 0; // Initialize a counter for occurrences of "is"

    // Loop through the string to find occurrences of "the" and "is"
    for (int i = 0; i < l; i++) {
      // Check for occurrences of "the" (a three-character substring)
      if (i < l - 2) {
        String tmp = stng.substring(i, i + 3);
        if (tmp.equals("the"))
          st_the++;
      }
      // Check for occurrences of "is" (a two-character substring)
      if (i < l - 1) {
        String tmp2 = stng.substring(i, i + 2);
        if (tmp2.equals("is"))
          st_is++;
      }
    }

    // Check if the counts of "the" and "is" occurrences are equal
    if (st_the == st_is)
      return true;
    else
      return false;
  }

  // Main method to execute the program
  public static void main(String[] args) {
    Main m = new Main(); // Create an instance of the Main class

    String str1 = "Thisisthethesis"; // Given input string

    // Display the given string and whether the appearances of "the" and "is" are equal
    System.out.println("The given string is: " + str1);
    System.out.println("Are the appearances of 'the' and 'is' equal? " + m.isAndTheEquality(str1));
  }
}