Java Questions

Q:

How can you avoid callback hells ?

Answer

There are lots of ways to solve the issue of callback hells:


1. Modularization: break callbacks into independent functions
2. Use a control flow library, like async
3. Use generators with Promises
4. Use async/await (note that it is only available in the latest v7 release and not in the LTS version)

Report Error

View answer Workspace Report Error Discuss

Subject: Java
Job Role: Analyst , IT Trainer

3 2645
Q:

Why interface method is always public?

Answer

To make this method available to every implementation class

Report Error

View answer Workspace Report Error Discuss

Subject: Java
Job Role: IT Trainer

0 2609
Q:

What is Overloading Polymorphism?

Answer

Overloading allows multiple functions to exist with same name but different parameters. Again if you take bike as an example, it has a function “Start” with two forms i.e. ’Auto Start’ and ’kick start’.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

0 2605
Q:

What is the purpose of declaring a variable as final?

Answer A final variable's value can't be changed. final variables should be initialized before using them.
Report Error

View answer Workspace Report Error Discuss

Subject: Java

0 2602
Q:

If a method is declared as protected, where may the method be accessed?

Answer

A protected method may only be accessed by classes or interfaces of the same package or by subclasses of the class in which it is declared.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

0 2565
Q:

What are the basic interfaces of Java Collections Framework ?

Answer

Java Collections Framework provides a well designed set of interfaces and classes that support operations on a collections of objects. The most basic interfaces that reside in the Java Collections Framework are:


Collection, which represents a group of objects known as its elements.


Set, which is a collection that cannot contain duplicate elements.


List, which is an ordered collection and can contain duplicate elements.


Map, which is an object that maps keys to values and cannot contain duplicate keys.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

1 2533
Q:

What is MultiThreading?

Answer

Executing two or more blocks (threads) of a program at a time is called MultiThreading.

Report Error

View answer Workspace Report Error Discuss

Subject: Java

0 2533
Q:

Which is a reserved word in the java programming language?

A) Variable B) Identifier
C) Keyword D) Main
 
Answer & Explanation Answer: C) Keyword

Explanation:

Reserved words are words that cannot be used as object or variable names in a Java program because they're already used by the syntax of the Java programming language.

Java reserved words are keywords that are reserved by Java functions or other uses that cannot be used as identifiers (e.g., variable names, function names, class names).

If a reserved word was used as a variable you would get an error or unexpected result.

 

Examples : Int, Long, Abstract, Class, Break, Catch, Case, Public, Static, Void,...

 

 

Report Error

View Answer Report Error Discuss

1 2522