what does this means while((s+ss) == null) ?

[naved momin]

public class AssingmentQuotes {

    /**
     * @param args the command line arguments
     */

    
    String s;

    String ss;
    void go ()
    {
    System.out.println(s + " " + ss);
         while((s+ss) == null )
        {
                 System.out.println("hi");
        }
    }



    public static void main(String[] args) {
        // TODO code application logic here
        new AssingmentQuotes().go();
    }

}

i think that the string has a null value by default ....so if i run this code what i was expecting that while loop should keep repeating and printing "hi" on the command line but that didnt happen
because of the statement

while(s+ss) == null)

now please explain me what s+ss returns or null or any different values

[naved momin]

naved momin wrote:

public class AssingmentQuotes {

    /**
     * @param args the command line arguments
     */

    
    String s;

    String ss;
    void go ()
    {
    System.out.println(s + " " + ss);
         while((s+ss) == null )
        {
                 System.out.println("hi");
        }
    }



    public static void main(String[] args) {
        // TODO code application logic here
        new AssingmentQuotes().go();
    }

}

i think that the string has a null value by default ....so if i run this code what i was expecting that while loop should keep repeating and printing "hi" on the command line but that didnt happen
because of the statement

while(s+ss) == null)

now please explain me what s+ss returns or null or any different values

i got that