Random number and letter generators

Question

I was curious if there were methods in java to randomly generate random numbers and uppercase and lowercase letters. i am creating a password generator for a project. i am still a little new to java also.

Answer 1

     import java.util.Random;

Code is

    Random r = new Random();
    Integer num = 0;
    for(int i=0;i<100;i++){
        num=r.nextInt(20000);
    System.out.println(num);
    }

Output : 12228 8875 10340 8898 11949 8184 14417 17284

Answer 2

Also you can use Math.random() for generating random number. To generate a random letter you need to generate a number between 0 and 26 and then add it to the char number of 'A' or 'a'. For example

int firstUppercaseIndex = (int)'A'; // for uppercase
int firstLowercaseIndex = (int)'a'; // for lowercase

for (int i = 0; i < 10; i++) {
    Random r = new Random();
    int letterIndex = r.nextInt(26); // random number between 0 and 26
    char randomLowercase = (char) (firstLowercaseIndex + letterIndex);
    char randomUppercase = (char) (firstUppercaseIndex + letterIndex);

    System.out.println("randomLowercase = " + randomLowercase);
    System.out.println("randomUppercase = " + randomUppercase);
}