java define println for class object

Question

In C++, one can implement the ostream operator << to be able to define how a class can be output to the stream cout << Class .

Is it possible in java to do something like out.println(Class) ?

Answer 1

System.out.print() calls the toString() method of the object passed to it. If you override the toString() method in your class, you can implement a custom behaviour there. Your class inherit the method from Object . Every class has Object as a superclass in java. Below is the default implementation.

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

The print method ( System.out.print(Object obj) ) looks like this

public void print(Object obj) {
    write(String.valueOf(obj));
}

and the String.valueOf(Object obj) method finally calls toString() .