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Should interfaces be in the same file?
When you don’t declare a package, a type is in the default package. So even if you just put the IServiceAnnouncer interface in a separate file, it will be available to HelloWorld . Just compile both files at the same time. Thus, it’s preferred to place public (and also non-public, btw) classes in separate files.
What is the difference between interface and classes?
Differences between a Class and an Interface: A class can be instantiated i.e, objects of a class can be created. An Interface cannot be instantiated i.e, objects cannot be created. Classes does not support multiple inheritance. Interface supports multiple inheritance.
Can Java interface have fields?
A Java interface is a bit like a Java class, except a Java interface can only contain method signatures and fields. A Java interface is not intended to contain implementations of the methods, only the signature (name, parameters and exceptions) of the method.
Can a class and interface be used in the same file?
Putting a class and an interface into the same file puts no limits on how either can be used. An interface can still be used for mocks etc in just the same way, even if it is in the same file as a class which implements it.
Is it possible to have public interface and public class in one.java file?
In a single .Java file, is it possible to have a public interface and a public class (which implements the interface) I’m new to Java coding and it is written on most places on the net that a .java file cannot contain more than 2 public class. I want to know if it is true for the interface and a class also. No, it’s not possible.
Can a base class be mocked like an interface?
Base classes can declare protected and public functions that can be accessed by derivations. Abstract Base classes can’t be mocked easily like interfaces. Base classes normally indicate type hierarchy (IS A) Class derivations may come to depend on some base behavior (have intricate knowledge of parent implementation).
How to avoid calling base class implementation of interface methods?
One way to work around this, of course, is to have only the MyMainClass implement the interface, and delegate calls that it does not wish to implement itself into the helper class from which it derives. This, however, is a cumbersome solution which I would like to avoid.
https://www.youtube.com/watch?v=4sxyDXt1igs