Nandhini Sridharan

Okay this is basically as part of method reference. While DefaultableImpl::new refers to constructor reference of DefaultableImpl class.

Thanks.

public static void main( String[] args ) {
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Defaulable defaulable = DefaulableFactory.create( DefaultableImpl::new );
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System.out.println( defaulable.notRequired() );
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defaulable = DefaulableFactory.create( OverridableImpl::new );
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System.out.println( defaulable.notRequired() );
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}

I recently came across the above code in one of the article. Though I understand that ::new is used to pass the instance of the class. I would love to really read and understand about ::new. Can someone has any article links about it?

Whatever I am trying to ask is that

The default method implementations in interface can be equivalent to the methods defined in the abstract class.
The methods declared in the interface is equivalent to the abstract methods in the abstract class


In a way, we are redefining the abstract class features in interface. With prior to Java 8, Interface has an advantage of multiple inheritance but abstract classes cannot.

But the advantage of the feature introduced in interface, to me is to have the backward compatibility. Meaning, the already existing contract between the interface and the classes would not be broken by defining the new methods within an interface.

Is there anything else other than this is happening with this new feature?

I would like to answer my question by myself

Thanks to the post https://coderanch.com/t/646488/java/java/Core-Java-benefits-lambda-expressions

The advantages of Lambda with respect to Java programming is that

1. It aids less typing (Without beating around the bush, just expresses the actual calculation being made and fading out unnecessary syntax information)
2. The above statement also serves in another way that the programmer is just interested in what is being done (the actual business logic) than the decorating code like public static all those blah blah blah
3. When we pass function as method parameter, the method really need to know what is the result of that function rather than how the result has been achieved

What is the typical difference between abstract class and interface with default methods

I am going over the new features of Java 8. One of them would be Lambda expressions.

I know with Lambda, we can pass functions as method parameters. With respect to mathematical operations, we can pass the function as method parameter. But in what way, does this functionality majorly improves the java capability? Meaning, how are we achieving the most of this functionality with respect to application development?

Can someone throw light on this one?

Thanks

Guys,

I want to learn thoroughly the latest new features introduced and introducing in Java 8 and Java 9.

Can someone lead me to the direction on where exactly I can get this info from?

Thanks,
Geetha

Thanks Frits

Thanks Frits

I certainly understand that the same question has been asked and replied in different way by Himai and some other person already.. in this thread https://coderanch.com/t/644912/java-EJB-SCBCD/certification/message-driven-bean-listener-interface

But my question context is little different, I certainly understand that there are many message listeners based on messaging types. If the message listener interface (Like MessageListener interface imposes one method onMessage()), has many methods (like in POJI), MDB has to implement all those methods and the resource adapter will pick up one thats needed?

A Message Driven bean listener interface may define more than one message listener method. The resource adapter will determine which method will be invoked

So, In a typical development environment, The MDB has to define all the methods that are required by Message Listener interface (atleast provide empty implementation for an unwanted message listener method), and the resource adapter will decide on which method to choose?

In chapter 3 on Frits EJB 3.1 notes, its been stated that

A Message Driven bean instance variables can contain state across the handling of messages (e.g. database connection or reference to an enterprise bean).

Q1. Can MDB contain reference to stateful session bean?
Q2. With the statement, instance variables can contain state across the handling of messages Are the stateful session bean state is carried over or as per the DI rule when the MDB instance is destroyed, the DI automatically removes the stateful session bean?

Thank you Himai and Frits

Thanks Frits

Hello, For Asynchronous method only REQUIRED, REQUIRES_NEW AND NOT_SUPPORTED transaction attributes are allowed.

https://docs.oracle.com/javaee/6/api/javax/ejb/TransactionAttributeType.html