here object a1 is of tyep AnInterface but reference of AnInterfaceImpl. Call method on this object is giving compile time error methodOne do not catch or throw Exception. But why
this compiles and with out and error or exception.
Joined: Jul 03, 2001
Hi,payal In statement AnInterface ai = new AnInterfaceImpl(); compile-time type of ai is AnInterface that methodOne() throws an Exception if you not catch it compile-time error occur, but statement AnInterfaceImpl ai = new AnInterfaceImpl(); compile-time type is AnInterfaceImpl that methodOne() dosen't throws an Exception so it compiles without error
Joined: Jul 14, 2001
To do away with the problem we could have a1.methodOne() in a try catch block or we could simply use a throws with the main() in ATest . Thanx , it cleared my doubt aswell . Rest w/ George
Joined: Apr 02, 2001
Hi, Would like to add that it is always better to program to an interface rather than program to a class.The advantage you get is you can change the stub without any requirement for client compilation.This cannot be possible when you program to a class. Hence,
AnInterface ai = new AnInterfaceImpl();
is better than
AnInterfaceImpl aii = new AnInterfaceImpl();
It is bad programming to implement the methodOne() without throwing an exception.Remember that the interface signifies responsibilities which every implementing class must adhere to.
Hope this helps, Sandeep SCJP2, OCSD(Oracle JDeveloper), OCED(Oracle Internet Platform) [This message has been edited by Desai Sandeep (edited July 25, 2001).]
<b>Sandeep</b> <br /> <br /><b>Sun Certified Programmer for Java 2 Platform</b><br /> <br /><b>Oracle Certified Solution Developer - JDeveloper</b><br /><b>-- Oracle JDeveloper Rel. 3.0 - Develop Database Applications with Java </b><br /><b>-- Object-Oriented Analysis and Design with UML</b><br /> <br /><b>Oracle Certified Enterprise Developer - Oracle Internet Platform</b><br /><b>-- Enterprise Connectivity with J2EE </b><br /><b>-- Enterprise Development on the Oracle Internet Platform </b>