String in java-1

1] what is a mutable String in java Explain with an example
→   Once we create a String, on that String if we try to perform any operation and if those changes get 
    reflected in the same object then such strings are called “Mutable String”.
    Example: StringBuffer, StringBuilder
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2]WAP to reverse a String
input= “PWSKILL”
→
import java. util.*;

public class ReverseString {
  public static void main(String[] args) {
    
    StringBuilder reversed = new StringBuilder(“PWSKILLS);
    reversed.append(original);
    reversed = reversed.reverse();
    System.out.println("The reversed string is: " + reversed);
  }
}

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3]Write a program to reverse a sentence while preserving the position
Input = Think Twice
Output = “Kniht viewt”

import java. util.Scanner;

public class ReverseSentence {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System. out.print("Enter a sentence: ");
    String original = input.next line();
    String[] words = original.split(" ");
    String reversed = "";
    for (int i = words.length - 1; i >= 0; i--) {
      reversed += words[i] + " ";
    }
    System.out.println("The reversed sentence is: " + reversed);
  }
}
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4] Write a program to sort a string Alphabetically
and import java. util.Scanner;
import java. util.Arrays;

public class SortString {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System. out.print("Enter a string: ");
    String original = input.next line();
    char[] chars = original.toCharArray();
    Arrays.sort(chars);
    String sorted = new String(chars);
    System. out.println("The sorted string is: " + sorted);
  }
}