Program to check whether the number is prime or not:                                                             

package quipoin.javaeasyprograms;
public class PrimeORNot {
    static boolean checkPrimeOrNot(int n) {
        int count = 0;
        for (int i = 2; i <= n / 2; i++) {
            if (n % i == 0)
                count++;
        }
        if (count == 0)
            return true;
        else
            return false;
    }
    public static void main(String[] args) {
        System.out.println(checkPrimeOrNot(19));
    }
}

Output:

true

Program to find the nth Prime Number of the series:

package quipoin.javaeasyprograms;
public class NthPrimeNumber {
    static  int printNthPrime(int x){
        int count,j=2,p=1,n=0;
        while(p<=x) {
            count=0;
            for (int i = 2; i <= j / 2; i++) {
                if (j % i == 0) {
                    count++;
                    break;
                }
            }
            if(count==0) {
                n=j;
                p++;
            }
            j++;
        }
        return n;
    }
    public static void main(String[] args) {
        System.out.println(printNthPrime(5));
    }
}

Output:

11

Program to find the number between two numbers:

package quipoin.javaeasyprograms;
import java.util.ArrayList;
import java.util.List;

public class PrimeBetweenTwoNumber {
    static List<Integer> findPrimeBetnTwo(int x, int y) {
        int count;
        List<Integer> ls= new ArrayList<>();
        do{
            count = 0;
            for (int j = 2; j <= x / 2; j++) {
                if (x % j == 0) {
                    count++;
                    break;
                }
            }
            if (count == 0) {
               ls.add(x);
            }
            x++;
        }while (x <= y);
        return  ls;
    }
    public static void main(String[] args) {
        System.out.println(findPrimeBetnTwo(5,12));
    }
}

Output:

[5, 7, 11]