- Java - Home
- Java - Overview
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- Java Vs. C++
- JVM - Java Virtual Machine
- Java - JDK vs JRE vs JVM
- Java - Environment Setup
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- Java - Comments
- Java - Basic Syntax
- Java - Variables
- Java - Data Types
- Java - Type Casting
- Java - Unicode System
- Java - User Input
- Java - Date & Time
Java Operators
- Java - Operators
- Java - Arithmetic Operators
- Java - Assignment Operators
- Java - Relational Operators
- Java - Logical Operators
- Java - Bitwise Operators
- Java Operator Precedence & Associativity
- Java - Unary Operators
Java Control Statements
- Java - Decision Making
- Java - If Else Statement
- Java - Switch Statement
- Java - Loop Control
- Java - For Loop
- Java - For-Each Loop
- Java - While Loop
- Java - Do While Loop
- Java - Break Statement
- Java - Continue Statement
Object Oriented Programming
- Java - OOPs Concepts
- Java - Object & Classes
- Java - Class Attributes
- Java - Class Methods
- Java - Methods
- Java - Variables Scope
- Java - Constructors
- Java - Access Modifiers
- Java - Inheritance
- Java - Aggregation
- Java - Polymorphism
- Java - Overriding
- Java - Method Overloading
- Java - Dynamic Binding
- Java - Static Binding
- Java - Instance Initializer Block
- Java - Abstraction
- Java - Encapsulation
- Java - Interfaces
- Java - Packages
- Java - Inner Classes
- Java - Static Class
- Java - Anonymous Class
- Java - Singleton Class
- Java - Wrapper Classes
- Java - Enums
- Java - Enum Constructor
- Java - Enum Strings
Java Built-in Classes
- Java - Number
- Java - Boolean
- Java - Characters
- Java - Arrays
- Java - Multi-Dimensional Arrays
- Java - Final Arrays
- Java - Math Class
Java File Handling
- Java - Files
- Java - Create a File
- Java - Write to File
- Java - Read Files
- Java - Delete Files
- Java - Directories
- Java - I/O Streams
Java Error & Exceptions
- Java - Exceptions
- Java - try-catch Block
- Java - try-with-resources
- Java - Multi-catch Block
- Java - Nested try Block
- Java - Finally Block
- Java - throw Exception
- Java - Exception Propagation
- Java - Built-in Exceptions
- Java - Custom Exception
- Java - Chained Exception
Java Multithreading
- Java - Multithreading
- Java - Thread Life Cycle
- Java - Creating a Thread
- Java - Starting a Thread
- Java - Joining Threads
- Java - Naming Thread
- Java - Thread Scheduler
- Java - Thread Pools
- Java - Main Thread
- Java - Thread Priority
- Java - Daemon Threads
- Java - Thread Group
- Java - Shutdown Hook
Java Synchronization
- Java - Synchronization
- Java - Block Synchronization
- Java - Static Synchronization
- Java - Inter-thread Communication
- Java - Thread Deadlock
- Java - Interrupting a Thread
- Java - Thread Control
- Java - Reentrant Monitor
Java Networking
- Java - Networking
- Java - Socket Programming
- Java - URL Processing
- Java - URL Class
- Java - URLConnection Class
- Java - HttpURLConnection Class
- Java - Socket Class
- Java - Generics
Java Collections
Java Interfaces
- Java - List Interface
- Java - Queue Interface
- Java - Map Interface
- Java - SortedMap Interface
- Java - Set Interface
- Java - SortedSet Interface
Java Data Structures
Java Collections Algorithms
Advanced Java
- Java - Command-Line Arguments
- Java - Lambda Expressions
- Java - Sending Email
- Java - Applet Basics
- Java - Javadoc Comments
- Java - Autoboxing and Unboxing
- Java - File Mismatch Method
- Java - REPL (JShell)
- Java - Multi-Release Jar Files
- Java - Private Interface Methods
- Java - Inner Class Diamond Operator
- Java - Multiresolution Image API
- Java - Collection Factory Methods
- Java - Module System
- Java - Nashorn JavaScript
- Java - Optional Class
- Java - Method References
- Java - Functional Interfaces
- Java - Default Methods
- Java - Base64 Encode Decode
- Java - Switch Expressions
- Java - Teeing Collectors
- Java - Microbenchmark
- Java - Text Blocks
- Java - Dynamic CDS archive
- Java - Z Garbage Collector (ZGC)
- Java - Null Pointer Exception
- Java - Packaging Tools
- Java - Sealed Classes
- Java - Record Classes
- Java - Hidden Classes
- Java - Pattern Matching
- Java - Compact Number Formatting
- Java - Garbage Collection
- Java - JIT Compiler
Java Miscellaneous
- Java - Recursion
- Java - Regular Expressions
- Java - Serialization
- Java - Strings
- Java - Process API Improvements
- Java - Stream API Improvements
- Java - Enhanced @Deprecated Annotation
- Java - CompletableFuture API Improvements
- Java - Marker Interface
- Java - Streams
- Java - Datetime Api
- Java 8 - New Features
- Java 9 - New Features
- Java 10 - New Features
- Java 11 - New Features
- Java 12 - New Features
- Java 13 - New Features
- Java 14 - New Features
- Java 15 - New Features
- Java 16 - New Features
Java APIs & Frameworks
Java Class References
- Java - Scanner
- Java - Arrays
- Java - Strings
- Java - Date
- Java - ArrayList
- Java - Vector
- Java - Stack
- Java - PriorityQueue
- Java - LinkedList
- Java - ArrayDeque
- Java - HashMap
- Java - LinkedHashMap
- Java - WeakHashMap
- Java - EnumMap
- Java - TreeMap
- Java - IdentityHashMap
- Java - HashSet
- Java - EnumSet
- Java - LinkedHashSet
- Java - TreeSet
- Java - BitSet
- Java - Dictionary
- Java - Hashtable
- Java - Properties
- Java - Collection
- Java - Array
Java Useful Resources
Java Online Quiz
Following quiz provides Multiple Choice Questions (MCQs) related to Core Java. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.
Q 1 - What of the following is the default value of an instance variable?
Answer : C
Explaination
Instance variables are assigned default values based on their types. For example, int variable is assigned 0 and an object type variable is assigned null as default value.
Answer : C
Explaination
The int data type is represented by 32-bit signed two's complement integer,
Minimum value: -231
Maximum value: 231-1
Answer : C
Explaination
String variable has default value of null if defined as an instance/static variable.
Q 4 - Which of the following is false about String?
B - String can be created using new operator.
Answer : C
Explaination
String is a object.
Answer : B
Explaination
It is not mandatory to have a default constructor in a class.
Q 6 - What is JIT compiler?
A - JIT improves the runtime performance of computer programs based on bytecode.
B - JIT is an application development framework.
C - JIT is an implementation of the Java Virtual Machine which executes Java programs.
Answer : A
Explaination
JIT, Just In-Time Compiler, improves the runtime performance of computer programs based on bytecode.
Q 7 - What is true about a final class?
A - class declard final is a final class.
B - Final classes are created so the methods implemented by that class cannot be overridden.
Answer : D
Explaination
Final classes are created so the methods implemented by that class cannot be overridden. It can't be inherited. These classes are declared final.
Q 8 - What happens when thread's sleep() method is called?
A - Thread returns to the ready state.
Answer : B
Explaination
When a task invokes its sleep() method, it returns to the waiting state.
Q 9 - Which arithmetic operations can result in the throwing of an ArithmeticException?
Answer : A
Explaination
Integer / and % can result in the throwing of an ArithmeticException.
Q 10 - When finally block gets executed?
A - Always when try block get executed, no matter exception occured or not.
B - Always when a method get executed, no matter exception occured or not.
C - Always when a try block get executed, if exception do not occur.
Answer : A
Explaination
Always when try block get executed, no matter exception occured or not.