Java删除字符replaceFirst的用法

import java.util.Scanner;

public class Demo {

  public static void main(String[] args) {
    Scanner str = new Scanner(System.in);
    String a = null;
    while (true) {
      a = str.next();
      if (a.contains("end")) {
        a = a.substring(0, a.length() - 3);
        break;
      }
    }
    String str2= str.next();
    Object[] objects = deleteSubString(a, str2);
    for (int i = 0; i < objects.length; i++) {
      System.out.println(objects[i]);
    }
    str.close();
  }

  public static Object[] deleteSubString(String str1, String str2) {
    Object[] arr = new Object[2];
    int b = 0;
    while (str1.contains(str2)) {
      str1 = str1.replaceFirst(str2, "");
      b++;
    }
    arr[0] = str1;
    arr[1] = b;
    return arr;
  }
}