What is the use of anonymous inner class?
An anonymous inner class can be useful when making an instance of an object with certain “extras” such as overloading methods of a class or interface, without having to actually subclass a class. Anonymous inner classes are useful in writing implementation classes for listener interfaces in graphics programming.
What is a Java anonymous class?
An anonymous class in Java is a class not given a name and is both declared and instantiated in a single statement. You should consider using an anonymous class whenever you need to create a class that will be instantiated only once.
What is the difference between inner class and anonymous class in Java?
A local inner class consists of a class declared within a method, whereas an anonymous class is declared when an instance is created. So the anonymous class is created on the fly or during program execution.
What is true about anonymous inner class?
It can extend exactly one class and can implement multiple interfaces. It can extend exactly one class and implement exactly one interface. It can implement multiple interfaces regardless of whether it also extends a class.
Can constructor be private?
Yes. Class can have private constructor. Even abstract class can have private constructor. By making constructor private, we prevent the class from being instantiated as well as subclassing of that class.
Can we override static method?
Static methods cannot be overridden because they are not dispatched on the object instance at runtime. The compiler decides which method gets called. Static methods can be overloaded (meaning that you can have the same method name for several methods as long as they have different parameter types).
What is an inner class in java?
Java inner class or nested class is a class that is declared inside the class or interface. We use inner classes to logically group classes and interfaces in one place to be more readable and maintainable. Additionally, it can access all the members of the outer class, including private data members and methods.
What is the advantage of inner class in java?
The main advantages of a nested (inner) class are: It shows a special type of relationship, in other words, it has the ability to access all the data members (data members and methods) of the main class including private. They provide easier code because it logically groups classes in only one place.
What is an interface why is it used in java?
Why do we use interface ? It is used to achieve total abstraction. Since java does not support multiple inheritance in case of class, but by using interface it can achieve multiple inheritance . It is also used to achieve loose coupling.
Can we override method in java?
Can we override java main method? No, because the main is a static method.
Can a class be private in java?
We can not declare top level class as private. … Java allows only public and default modifier for top level classes in java. Inner classes can be private.
Is inner class a good practice?
Any additional encapsulation, such as making the entire inner class private , is desirable; but public inner classes are perfectly acceptable. There are many examples in Java, such as AbstractMap.
What’s meant by anonymous class?
Anonymous classes enable you to make your code more concise. They enable you to declare and instantiate a class at the same time. They are like local classes except that they do not have a name. Use them if you need to use a local class only once.
What does float a 35 0 return mean?
10) What does the expression float a = 35 / 0 return? Explanation: In Java, whenever we divide any number (double, float, and long except integer) by zero, it results in infinity.
Are all methods in an interface public?
All abstract, default, and static methods in an interface are implicitly public , so you can omit the public modifier. In addition, an interface can contain constant declarations. All constant values defined in an interface are implicitly public , static , and final .