Help me modify my MaxSentinel Java Program(Attached image & Pasted Java Code) into a new program called MaximumSent... 1. Check for valid first entry. Then allow the user to enter as many numbers as desired. 2. If invalid number entered, print "Invalid entry." Prompt the user again until a valid number is entered.  3. Once -1 is entered, program stops and prints the largest number entered. Submit final code.   JAVA CODE for MaxSentinel, has been pasted below: (also view attached images) import java.util.Scanner; public class MaxSentinel {    public static void main(String[] args) {        Scanner input=new Scanner(System.in);        int num=0,max=-1;        System.out.print("Enter positive integers(-1 to stop):");        num=input.nextInt();        while(num!=-1)        {            if(num>max)                max=num;            System.out.print("Enter positive integers(-1 to stop):");            num=input.nextInt();        }        System.out.println("Largest number: "+max);    } }

Java code

1. Write Java code to repeatedly print each single digit between 1 and 9 the number of times based upon its numeric value. Thus, you would get a triangle of the shape below where 1 prints once, 2 twice . and 9 prints 9 times. 1 22 333 4444 55555 666666 7777777 88888888 999999999

In Java 8, I want the program to capture the current year and compare it to an input value. Specifically, the user is asked to enter the last two digits of a year that will be output. If those two digits are greater than the last two digits of the current year, the program will print to console a “19” before the two digits the user inputted. If the two digits that the use input are less than or equal to the last two digits of the current year, the program will print to the console a “20” before the two digits the user inputted. For instance, if the current year is 2023, and the user input the integer number “74”, the program would output to the console “1974”. If the current year is 2023, and the user input the integer number “19”, the program would output to the console “2019”. The user is not asked to enter the current year; the program captures that automatically. The user only enter the last two numbers of a year. Hopefully, that's enough to go by and clear enough. I need the code,…