Enter pattern number: 1

Enter number of lines: 5

ABCDE

ABCD

ABC

AB

A

class Pattern {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.print("Enter pattern number: ");
    int choice = scanner.nextInt();
    if (choice == 1) {
      System.out.print("Enter number of lines: ");
      int n = scanner.nextInt();
      for (int i = n; i >= 1; i--) {
        for (int j = 0; j < i; j++) {
        System.out.print((char) ('A' + j));
        }
      System.out.println();
   }
   } else if (choice == 2) {
     System.out.print("Enter string: ");
     String s = scanner.next();
     for (int i = 0; i < s.length(); i++) {
     char ch = s.charAt(i);
     for (int j = 1; j <= (i + 1); j++) {
     System.out.print(ch);
     }
       System.out.println();
     }
     } else {
    System.out.println("Invalid choice");
    }
  }
}

-OR-

import java.util.*;
class MenuPattern 
{
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("1. Pattern 1");
        System.out.println("2. Pattern 2");
        System.out.print("Enter your choice: ");
        int choice = sc.nextInt();
        switch(choice){
            case 1:
                String s = "ABCDE";
                for(int i = s.length(); i >= 0; i--)
                    System.out.println(s.substring(0, i));
                break;
            case 2:
                s = "BLUE";
                for(int i = 0; i < s.length(); i++){
                    char ch = s.charAt(i);
                    for(int j = 0; j <= i; j++)
                        System.out.print(ch);
                    System.out.println();
                }
                break;
            default:
                System.out.println("Invalid choice!");
        }
    }
}