Method Overriding in Java

public class First {

public void abc ()
{
System.out.println("First");
}

public void xyz ()
{
System.out.println("First_XYZ");
}
}

------------------------------------------------------------------------------------------

public class Second extends First {
public void abc ()
{
System.out.println("Second");
}

public static void main(String args[])
{
First first = new First();
first.abc();//First

Second sec = new Second();
sec.abc();//Second

First cc = new Second();
cc.abc();//Second

Object a = new Second();
System.out.println(a.getClass());//class Second

First fs = (First) new Second();
fs.abc();//Second



/************************************/
First c = new Second();
c.xyz();//First_XYZ as there is no xyz() method in this class

First f = (First) new Second();
f.xyz();//First_XYZ as there is no xyz() method in this class

/************************************/
Second dd = (Second) new First();
dd.abc();//java.lang.ClassCastException: First cannot be cast to Second

}
}

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First
Second
Second
class Second
Second
First_XYZ
First_XYZ
java.lang.ClassCastException: First cannot be cast to Second
at Second.main(Second.java:34)