signature object in java code example

Example 1: object orientation in java

class Person {
 void walk() {
  System.out.println(“Can Run….”);
 }
}
class Employee extends Person {
 void walk() {
  System.out.println(“Running Fast…”);
 }
 public static void main(String arg[]) {
  Person p = new Employee(); //upcasting
  p.walk();
 }
}

Example 2: string method example in java

public String concat(String s)

String x = "book";
System.out.println( x.concat(" author") ); // output is "book author"