Which of the following do not support JSP directly?

Which of the following do not support JSP directly?

Apache HTTP Server do not supports JSP directly.

What are thread issues in servlet?

Most servlet threading problems occur when two or more threads make changes to the same resource. This might mean that two threads try to modify a file, or perhaps several threads all update the value of a shared variable at the same instant.

Can you override interface methods?

If a base class already implements an interface and a derived class needs to implement the same interface but needs to override certain methods, you must reimplement the interface and set only the interface methods which need overriding. Both implement the ViewerEditable interface. …

Do I have to implement all interface methods?

Yes, it is mandatory to implement all the methods in a class that implements an interface until and unless that class is declared as an abstract class. Declare the class as an abstract class, as a result, forces you to subclass the class (and implement the missing methods) before you can create any objects.

Can we override default method?

If you have default method in an interface, it is not mandatory to override (provide body) it in the classes that are already implementing this interface. In short, you can access the default methods of an interface using the objects of the implementing classes.

Why interface has only static and final variables?

Interface variables are static because java interfaces cannot be instantiated on their own. The value of the variable must be assigned in a static context in which no instance exists. The final modifier ensures the value assigned to the interface variable is a true constant that cannot be re-assigned.

Can a variable be static and final?

Static variables are stored in the static memory, mostly declared as final and used as either public or private constants. Static variables are created when the program starts and destroyed when the program stops. Visibility is similar to instance variables.

Can an interface contain a constructor?

Constructor in an interface An Interface in Java doesn’t have a constructor because all data members in interfaces are public static final by default, they are constants (assign the values at the time of declaration).

Can abstract class have constructor?

The constructor inside the abstract class can only be called during constructor chaining i.e. when we create an instance of sub-classes. This is also one of the reasons abstract class can have a constructor.

Can abstract class have body?

Abstract methods cannot have body. Abstract class can have static fields and static method, like other classes. An abstract class cannot be declared as final. Only abstract class can have abstract methods.

Can we make abstract class as final?

Yes, there may be “final” methods in “abstract” class. But, any “abstract” method in the class can’t be declared final. It will give “illegal combination of modifiers: abstract and final” error.

Can an abstract class be instantiated?

Abstract classes cannot be instantiated, but they can be subclassed. When an abstract class is subclassed, the subclass usually provides implementations for all of the abstract methods in its parent class. However, if it does not, then the subclass must also be declared abstract .

Why can’t you instantiate an abstract class?

Abstract class, we have heard that abstract class are classes which can have abstract methods and it can’t be instantiated. We cannot instantiate an abstract class in Java because it is abstract, it is not complete, hence it cannot be used.