[Java] Can someone help me with this program.

I believe i need a main class in order for this program below to work.

I'm trying to validate a credit card number...the error I get running this is "Static Error: This class does not have a static void main method accepting String[]."

public class CreditCard {

private long cardNumber;

private int finalSum;

public CreditCard()

{

cardNumber = 0;

}

public CreditCard(long num)

{

cardNumber = num;

}

public void setCardNumber(long num)

{

cardNumber = num;

}

public long getCardNumber()

{

return cardNumber;

}

public boolean validateNumber()

{

finalSum = 0;

long n = cardNumber;

int sum1 = 0, sum2 = 0;

int rem;

for(int i = 0; i < 8; i++)

{

rem =(int) (n % 10);

if(i % 2 == 0)

sum1 += rem;

else

sum2 += sumDigits(rem * 2);

n = n / 10;

}

finalSum = sum1 + sum2;

if(finalSum % 10 == 0)

return true;

else

return false;

}

private int sumDigits(int n)

{

int sum = 0;

while( n != 0)

{

sum += n % 10;

n = n /10;

}

return sum;

}

public void display()

{

if(validateNumber())

System.out.println("The credit card number is valid");

else

{

int lastDigit =(int)( (cardNumber - finalSum + 10) % 10);

System.out.println("The credit card number is not valid");

System.out.println("The last digit should be " + lastDigit);

}

}

}