Object class toString() method will call internally by default whenever we print
object reference even though object contains content.
public class StudentRecord {
public static void main(String[] args) {
Student
s1=new Student(10);
System.out.println(s1); //output :
Student@1db9742
}
}
class Student{
int id;
Student(int id){
this.id=id;
}
}
We got the output:
Student@1db9742 even we passed id=10
Whenever object class toString()
called, internally it call hashCode()
Internal code of toString()
public String toString()
{
return getClass().getName() + "@" + Integer.toHexString(hashCode());
}
toString() return output as
Class
name @ hexadecimal hashcode
If we override toString() method in our class then
toString() method don’t call hashcode() method.
public class StudentRecord {
public static void main(String[] args) {
Student
s1=new Student(10);
System.out.println(s1); //output : Student
id : 10
}
}
class Student{
int id;
Student(int id){
this.id=id;
}
@Override
public String toString() {
return "Student id :
"+id;
}
}
Whenever we override toString() method in our class it
returns exact content of object (meaningful representation).
Above program gives output as: Student id : 10
Note: String class overridden toString()
method and it give meaningful representation by default
Example:
public class Test {
public static void main(String[] args) {
String s1=new String("hello world");
System.out.println(s1);// hello world
}
}
In this program we doesn’t override toString() method any
where even though it given exact output because we taken String class.
