write a snippet using Java language

.Accept an input and check if it is an integer.

.Accept three numbers and to print the largest value.

.Accept an input and prints the closet integer. for example if the user inputs 6.25, then closet integer is 6, if the user inputs 6.75, then closet integer is 7

. In the UK, purchase of certain items such as Alcohol drinks and Tobacco products requires age check. Asks the user for their year of birth, if the person is older than 23 years old, then print (" Purchase Permitted" ), if not , print "Purchase not permitted due to age restrictions".

ie please write the code by using excel sheet or Intellij Idea