Can we have different return type in method overriding in java?

Problem statement: can we have different return type in method overriding in java

Yes ! it may differ but their are some limitations. 
Before Java 5.0, when you override a method, both parameters and return type must match exactly. 
In Java 5.0, it introduces a new facility called covariant return type. You can override a method with the same signature but returns a subclass of the object returned. In another words, a method in a subclass can return an object whose type is a subclass of the type returned by the method with the same signature in the superclass.
For example:
class OverridingExe2 {
    public Object run() {
        System.out.println("object");
        return null;
    }
}
public class OverridingExe1 extends OverridingExe2 {
    public String run() { // covariant return type from java 5.0
        System.out.println("string");
        return null;
    }
    public static void main(String args[]) throws Exception {
        OverridingExe2 r = new OverridingExe1();
        r.run();
    }
}
Output:
string