Books

Learn HTML Learn CSS Learn Git Learn Javascript Learn PHP Learn python Learn Java

Exercises

HTML JavaScript Git CSS PHP

Courses Quizzes Snippets

Tools

General Tools

Password Generator
HTML Editor
HTML Encoder
Base 64
Code Diff
JSON Beautifier
CSS Beautifier
Markdown Convertor
Find the Closest Tailwind CSS Color
Phrase encrypt / decrypt
Browser Feature Detection
Number convertor

CSS Maker

CSS Maker
CSS Maker text shadow
CSS Maker Text Rotation
CSS Maker Out Line
CSS Maker RGB Shadow
CSS Maker Transform
CSS Maker Font Face

Color Tools

Color Picker
Colors CMYK
Colors HWB
Colors HSL
Color Hex
Color mixer
Color Converter
Colors RGB
Color Contrast Analyzer
Color Gradient

String Tools

String Length Calculator
MD5 Hash Generator
Sha256 Hash Generator
String Reverse
URL Encoder
URL Decoder
Base 64 Encoder
Base 64 Decoder
Extra Spaces Remover
String to Lowercase
String to Uppercase
Word Count Calculator
Empty Lines Remover
HTML Tags Remover
Binary to Hex
Hex to Binary
Rot13 Transform on a String
String to Binary
Duplicate Lines Remover

Books
How To

Java Basics

1/25 In Java, which of the following is a correct way to create a thread?
- Implementing the Runnable interface
- Extending the Thread class
- Extending the Runnable interface
- Implementing the Thread class
2/25 Which method is called when an object is cloned in Java?
- cloneMethod()
- copy()
- clone()
- Object.clone()
3/25 Which Java feature allows the method of a subclass to override the method of its superclass?
- Inheritance
- Encapsulation
- Polymorphism
- Abstraction
4/25 How do you handle exceptions in Java?
- Using try-catch blocks
- By using the 'throws' keyword
- By using the 'extends' keyword
- By declaring them as static
5/25 What does the '@Override' annotation do in Java?
- Indicates that a method is being replaced from the parent class
- Marks a method that cannot be overridden
- Overrides the default values of variables
- Signals the use of overridden methods from an interface
6/25 What is 'autoboxing' in Java?
- Automatically converting a primitive type into its corresponding wrapper class
- The process of optimizing code automatically
- Creating an automatic backup of the code
- A feature for automatic memory management
7/25 How do you declare a constant variable in Java?
- Using the 'constant' keyword
- Using the 'static final' keywords
- Using the 'immutable' keyword
- Declaring without initialization
8/25 In Java, what is the purpose of the Collections.sort() method?
- To sort elements of a collection in descending order
- To randomly shuffle elements of a collection
- To sort elements of a collection in ascending order
- To reverse the order of elements in a collection
9/25 What is the concept of 'overloading' in Java?
- Assigning extra resources to a Java application
- Creating multiple methods in a class with the same name but different parameters
- Increasing the memory allocation to a Java program
- Replacing a method in a subclass with a method from the superclass
10/25 Which Java feature allows runtime binding of method calls?
- Static Typing
- Dynamic Binding
- Method Overloading
- Method Overriding
11/25 In Java, what is a 'Lambda Expression'?
- A concise representation of an anonymous function that can be passed around
- A special type of exception
- A way to create a new thread
- An expression used for array manipulation
12/25 Which method is used to compare two strings for equality in Java?
- compareTo()
- equals()
- equalsIgnoreCase()
- compare()
13/25 What does the 'synchronized' keyword ensure in a multi-threaded environment?
- Faster execution of threads
- That only a single thread can access the method or block at a time
- That multiple threads can execute the method concurrently
- That the method will always be executed by the main thread
14/25 What is 'garbage collection' in Java?
- A process of deallocating memory by manually deleting objects
- A process of automatically freeing memory occupied by objects that are no longer in use
- A tool for optimizing Java code
- A method for storing unused objects
15/25 How do you create a thread-safe singleton in Java?
- Using double-checked locking
- By making all methods synchronized
- By declaring all variables as volatile
- By using a static class
16/25 What is the difference between 'static' and 'non-static' methods in Java?
- Static methods can be called without creating an instance of the class
- Non-static methods are always synchronized
- Static methods are faster
- Non-static methods can access any class variable
17/25 What does the 'throws' keyword do in Java?
- Automatically handles an exception
- Declares an exception which might be thrown
- Stops the propagation of an exception
- Increases the throw range of an exception
18/25 In Java, what is a 'checked' exception?
- An exception that is checked at compile-time
- An exception that is checked at runtime only
- Any exception that occurs during program execution
- An exception that cannot be caught or handled
19/25 Which method in the Object class is used to obtain a unique hash code for the object?
- uniqueCode()
- hashCode()
- identityHashCode()
- getObjectHash()
20/25 What is 'encapsulation' in Java?
- The technique of wrapping code and data together into a single unit
- A process of linking a method with an object
- A method of improving code execution time
- The division of a program into smaller parts
21/25 In Java, what is the function of the 'super' keyword?
- To call a method of the superclass
- To declare superior variables
- To access the superclass's static methods
- To create an object of the superclass
22/25 What is 'polymorphism' in the context of Java?
- The ability of a variable to hold objects of different types
- The ability of Java to run on different platforms without modification
- The ability of a method to perform different tasks based on the object
- Changing the behavior of an object at runtime
23/25 In Java, what is the purpose of the 'enum' keyword?
- To define a new exception type
- To declare a collection of constants
- To create an enumeration of values for iteration
- To optimize memory usage in large applications
24/25 What is the use of the 'protected' access modifier in Java?
- To restrict access to the class members within its own class only
- To provide access to the class members within the same package and subclasses
- To provide universal access from any other class
- To prevent modification of the class members
25/25 In Java, what is 'exception chaining'?
- Linking multiple exceptions together
- Creating a chain of methods that can throw exceptions
- Catching multiple exceptions in one catch block
- Calling a method that throws an exception from another that also throws an exception
To get the result of the quiz, please provide your email address (optional)..

It seems you haven't answered any questions yet. Please provide your answers to proceed.

Quizzes
Snippets
Our Books
- Learn HTML
- Learn CSS
- Learn Git
- Learn Javascript
- Learn PHP
- Learn python
- Learn Java
- Exercises
- HTML
- JavaScript
- Git
- CSS
- PHP
Our Tools

About Us
Privacy Policy for W3Docs

Follow Us

Company © W3docs. All rights reserved.