- Java - Home
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Java Operators
- Java - Operators
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Java Control Statements
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Object Oriented Programming
- Java - OOPs Concepts
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Java Built-in Classes
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Java File Handling
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Java Error & Exceptions
- Java - Exceptions
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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
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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
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- Java - Generics
Java Collections
Java Interfaces
- Java - List Interface
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- Java - SortedSet Interface
Java Data Structures
Java Collections Algorithms
Advanced Java
- Java - Command-Line Arguments
- Java - Lambda Expressions
- Java - Sending Email
- Java - Applet Basics
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- 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
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- Java - Optional Class
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- Java - Base64 Encode Decode
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- Java - Dynamic CDS archive
- Java - Z Garbage Collector (ZGC)
- Java - Null Pointer Exception
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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
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- 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 a local variable?
Answer : D
Explaination
Local variables are not assigned any value by default.
Answer : B
Explaination
The char data type is represented by single 16-bit Unicode character.
Minimum value: '\u0000' (or 0)
Maximum value: '\uffff' (or 65,535)
Answer : A
Explaination
int variable has default value of 0 if defined as an instance/static variable.
Q 4 - Which of the following is true about String?
Answer : B
Explaination
String object is immutable so that once it is created a String object cannot be changed. Since String is immutable it can safely be shared between many threads which are considered very important for multithreaded programming.
Q 5 - What is local variable?
A - Variables defined inside methods, constructors or blocks are called local variables.
B - Variables defined outside methods, constructors or blocks are called local variables.
C - Static variables defined outside methods, constructors or blocks are called local variables.
Answer : A
Explaination
Variables defined inside methods, constructors or blocks are called local variables. The variable will be declared and initialized within the method and it will be destroyed when the method has completed.
Answer : B
Explaination
No, this is not possible.
Q 7 - What is function overloading?
A - Methods with same name but different parameters.
B - Methods with same name but different return types.
C - Methods with same name, same parameter types but different parameter names.
Answer : A
Explaination
If a class has multiple functions by same name but different parameters, it is known as Method Overloading.
Q 8 - What is Deserialization?
A - Deserialization is the process of restoring state of an object from a byte stream.
B - Serialization is the process of restoring state of an object from an object.
Answer : A
Explaination
Deserialization is the process of restoring state of an object from a byte stream.
Q 9 - Under what conditions is an object's finalize() method invoked by the garbage collector?
A - When it detects that the object has become unreachable.
B - As soon as object is set as null.
Answer : A
Explaination
The garbage collector invokes an object's finalize() method when it detects that the object has become unreachable.
Q 10 - Which of the following is a marker interface?
Answer : A
Explaination
serializable is a marker interface.