How Java determines whether a character is a number or a letter

In C + +, you can use IsDigit () to determine whether a character is a number, you can use Isalpha () to determine whether a character is a letter, and many, all in the <cctype> header file

A similar approach in Java is primarily a static method of the character class:

Character.isdigit (char ch)   //Determine if CH is a numeric character, such as ' 1 ', ' 2 ', is the return true. otherwise returns false

Character.isletter (char ch)//Determine if CH is an alphabetic character, such as ' A ', ' B ', is returned true. otherwise returns false

Character.isletterordigit (char ch)//Determine if CH is a letter or numeric character, such as ' A ', ' B ', ' 1 ', ' 2 ', is the return true. otherwise returns false

How Java determines whether a character is a number or a letter