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Java Java Data Structures - Retired Getting There Packages

Posted by Garvit Kashyap
Garvit Kashyap
2,918 Points

How does the putting "treet" in the System.out.printf line print the package name ?

import com.teamtreehouse.Treet; public class Example {

public static void main (String[] args) { Treet treet = new Treet(); System.out.printf("This is a new Treet: %s %n", treet);

}

}

Output: This is a new Treet: com.teamtreehouse.Treet@7852e922

I wanted to ask how in the last line of code, putting "treet" prints out the package name i.e., com.treehouse.Treet ?

1 Answer

andren
andren
28,558 Points
andren
andren
28,558 Points

When you pass printf an object it will automatically call that objects toString method, at least when the %s placeholder is used. By default an object's toString method will simply print out the name of the class along with it's hashcode. The default toString method basically looks like this:

public static String toString(Object o) {
    return o.getClass().getName() + "@" + Integer.toHexString(o.hashCode());
}

So it's due to that method being called that you end up with having the class name (which includes the package info) printed out.

Garvit Kashyap
Garvit Kashyap
2,918 Points

Thank you so much andren. I get it now.