- Can we declare constructor as static?
- Can method be overloaded?
- What is a top level class in Java?
- Can I declare class as static or private?
- What is difference between == and equals?
- When should a method be private?
- Can a constructor be final?
- What is private keyword in Java?
- Is class private in Java?
- Can we extend private class in Java?
- Can private class have public constructor?
- Can we inherit a constructor?
- Is void a keyword in Java?
- Can a constructor be overloaded?
- What do you call a constructor that accepts no arguments?
- What does a private class mean?
- Can we declare class as final in Java?
- Can we override static method?
- When should you make a class static?
- Can we create object for private class?
- Why can’t we declare a class as private in Java?
Can we declare constructor as static?
No, we cannot define a static constructor in Java, If we are trying to define a constructor with the static keyword a compile-time error will occur.
In general, static means class level.
A constructor will be used to assign initial values for the instance variables..
Can method be overloaded?
In Java, two or more methods can have same name if they differ in parameters (different number of parameters, different types of parameters, or both). These methods are called overloaded methods and this feature is called method overloading. For example: … These methods have the same name but accept different arguments.
What is a top level class in Java?
A top level class is a class that is not a nested class. A nested class is any class whose declaration occurs within the body of another class or interface.
Can I declare class as static or private?
So, Yes, you can declare a class static in Java, provided the class is inside a top-level class. Such clauses are also known as nested classes and they can be declared static, but if you are thinking to make a top-level class static in Java, then it’s not allowed.
What is difference between == and equals?
In simple words, == checks if both objects point to the same memory location whereas . equals() evaluates to the comparison of values in the objects. Explanation: Here we are creating two objects namely s1 and s2. Both s1 and s2 refers to different objects.
When should a method be private?
Private methods are useful for breaking tasks up into smaller parts, or for preventing duplication of code which is needed often by other methods in a class, but should not be called outside of that class.
Can a constructor be final?
No, a constructor can’t be made final. A final method cannot be overridden by any subclasses. … In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.
What is private keyword in Java?
The private keyword is an access modifier used for attributes, methods and constructors, making them only accessible within the declared class.
Is class private in Java?
Java doesn’t allow a top level class to be private. Only ‘public’ or ‘package’. … If a class has no modifier (the default, also known as package-private), it is visible only within its own package (packages are named groups of related classes — you will learn about them in a later lesson.)
Can we extend private class in Java?
1) In Java, inner Class is allowed to access private data members of outer class. This behavior is same as C++ (See this). 2) In Java, methods declared as private can never be overridden, they are in-fact bounded during compile time.
Can private class have public constructor?
Modifiers public, protected and, private are allowed with constructors. We can use a private constructor in a Java while creating a singleton class. The Singleton’s purpose is to control object creation, limiting the number of objects to only one.
Can we inherit a constructor?
Constructors are not members, so they are not inherited by subclasses, but the constructor of the superclass can be invoked from the subclass.
Is void a keyword in Java?
The void keyword specifies that a method should not have a return value.
Can a constructor be overloaded?
Yes! Java supports constructor overloading. In constructor loading, we create multiple constructors with the same name but with different parameters types or with different no of parameters.
What do you call a constructor that accepts no arguments?
In both Java and C#, a “default constructor” refers to a nullary constructor that is automatically generated by the compiler if no constructors have been defined for the class. … A programmer-defined constructor that takes no parameters is also called a default constructor in C#, but not in Java.
What does a private class mean?
Unlike a class, an inner class can be private and once you declare an inner class private, it cannot be accessed from an object outside the class. Following is the program to create an inner class and access it. In the given example, we make the inner class private and access the class through a method.
Can we declare class as final in Java?
You can declare some or all of a class’s methods final. You use the final keyword in a method declaration to indicate that the method cannot be overridden by subclasses. … Note that you can also declare an entire class final. A class that is declared final cannot be subclassed.
Can we override static method?
Can we Override static methods in java? We can declare static methods with the same signature in the subclass, but it is not considered overriding as there won’t be any run-time polymorphism. Hence the answer is ‘No’.
When should you make a class static?
Use a static class to contain methods that are not associated with a particular object. For example, it is a common requirement to create a set of methods that do not act on instance data and are not associated to a specific object in your code. You could use a static class to hold those methods.
Can we create object for private class?
yes. private is an access modifier, as you might have learned that restricts member to be access just within declaring scope. So as a member of another class , private class can be accessed in that class only.
Why can’t we declare a class as private in Java?
A top-level class as private would be completely useless because nothing would have access to it. … This means that a top level class cannot be private. Private classes are allowed but only as inner or nested classes. If you have a private inner or nested class, then access is restricted to the scope of that outer class.