isPrime Program -review required

Hi, I have written Java program for finding prime number…anyone to review and comment:

// Import statement:
import java.util.ArrayList;

class PrimeDirective {

// Add your methods here:
public boolean isPrime(int number){

if (number ==2){
  return true;
} else if(number <2){
  return false;
}

for (int i=2; i<number; i++){
  if ((number%i)==0){
    return false;
  }  
  
}

return true;
}

public ArrayList onlyPrimes(int numbers){
ArrayList primes =new ArrayList();
for (int number: numbers){
if (isPrime(number)){
primes.add(number);
}
}
return primes;
}

public static void main(String args) {

PrimeDirective pd = new PrimeDirective();
int[] numbers = {6, 29, 28, 33, 11, 100, 101, 43, 89};
System.out.println(pd.onlyPrimes(numbers));

}
}

It should be public ArrayList only Primes and ArrayList primes = new ArrayList() . Since Array is immutable and Arraylist is mutable!