Question

I am doing one application in android for that I need to access com.android.internal.telephony APIs. Now I am able to access those APIs but problem is wherever I call the getEarliestConnection() method of Class Call.java in my own class it’s throwing a NullPointerException.
You can find Call.java here http://hi-android.info/src/com/android/internal/telephony/Call.java.html. In this class there is the following method:

1.    public Connection
2.        getEarliestConnection() {
3.            List l;
4.            long time = Long.MAX_VALUE;
5.            Connection c;
6.            Connection earliest = null;
7.    
8.            l = getConnections();
9.  
10.            if (l.size() == 0) {
11.                return null;
12.            }

        for (int i = 0, s = l.size() ; i < s ; i++) {
            c = (Connection) l.get(i);
            long t;

            t = c.getCreateTime();

            if (t < time) {
                earliest = c;
                time = t;
            }
        }

        return earliest;
    }

I want to call this method in my class. the class Call.java ia an abstract class I created subclass of Call class and called the above method like this:

Call myCall = new MyCall();
Connection myConn = new MyConn();
myConn = myCall.getEarliestConnection();  

But It’s throwing a NullPointerException on line no:10 of above method and line no:3 of above code.

Answer 1

Obviously getConnections() returns null here and you cannot get the size of the null-object.

Here’s how to fix it:

if (l == null || l.size() == 0) 
{
    return null;
}

So, if for some unknown reason, there is no Connection-List or the list is empty, null will be returned. Using the operator || will do the same as

if (l == null)
{
    return null;
}
else if ( l.size() == 0)
{
    return null;
}