How to validate a Long data type field in java

Question

I have a Long field in java.I need to test whether this field has a value or not.I am using the following code:

        Long phone_temp = queryAllPhoneNumbersForContact(contactId);
        if(phone_temp.equals(""))
        {
          System.out.println("Value  is null",""+phone_temp);
        }                       

Long has a null value however when i try to print the value of phone_temp it gives app crashed.How do i check whether phone_temp has a value.

Answer 1

java.lang.Long would never be an empty string. If it doesn't have a value means its null . If queryAllPhoneNumbersForContact(contactId) returns a long wrapper instance then check phone_temp ==null , as objects have default value as null.

Long phone_temp = queryAllPhoneNumbersForContact(contactId);
            if(phone_temp==null)