This will work for generating a number 1 - 10. Make sure you import Random at the top of your code.
import java.util.Random;
If you want to test it out try something like this.
Random rn = new Random();
for(int i =0; i < 100; i++)
{
int answer = rn.nextInt(10) + 1;
System.out.println(answer);
}
Also if you change the number in parenthesis it will create a random number from 0 to that number -1 (unless you add one of course like you have then it will be from 1 to the number you've entered).