Top Java MCQs Questions And Answers
Explore the Top Java MCQs Questions And Answers to test your knowledge. Perfect for beginners and professionals preparing for Java exams and interviews.
Can we override final methods in Java?
A.yes
B.no
Ans:B
break keyword used only inside
A.if statements
B.class and loops
C.switch case and loops
D.loops and if statements
Ans:C
Which method is called internally when Thread start() method? A.execute()
B.run()
C.start()
D.yeild()
Ans:B
What is the maximum thread priority in java?
A.5
B.9
C.20
D.10
Ans:D
Which method should be implemented by Java thread? A.run()
B.start()
C.wait()
D.sleep()
Ans:A
How many threads are created in the java program? public class ThreadExtended extends Thread {
public void run() {
System.out.println(“\nThread is running now\n”);
}
public static void main(String[] args) {
ThreadExtended t1= new ThreadExtended();
t1.start();
}
}
A.1
B.0
C.2
D.3
Ans:C
By how many ways thread can be created in java multithreading
A.1
B.0
C.2
D.3
Ans:2
Which statement is correct about the thread
A. On calling the thread start method a new thread gets created
B. Thread start() method can call run() internally
C. The thread run method can not be called directly to create a thread
D. All are correct
Ans:D
Which method is used to create the main thread to wait for all child threads A.Stop
B.wait
C.join
D.sleep
Ans:C
The default thread priority of java thread is
- 6
- 0
- 1
- 5
Ans:D
Which method is used to check if the thread is alive?
A.alive()
B.isAlive()
C.run()
D.start()
Ans: B
The task performed by the daemon thread is
A.to serve user thread
B. Perform garbage collection
C.both 1 and 2
D.none of the above
Ans: C
Which method is used to create a daemon thread in java? A.setDaemon()
B.createDaemon()
C.Daemon()
D.makeDaemon()
Ans:A
wait(),notify(),notifyAll() methods belong to which class? A.System
B.String
C.Thread
D.Object
Ans:D
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The life cycle of thread in java is controlled by A.JDK
B.JRE
C.JVM
D.None of the above
Ans: C
Thread synchronization is achieved by using which method A.wait()
B.run()
C.synchronized
D.syn()
Ans:C
Which of these methods deletes all the elements from invoking collection?
A. Clear()
B. delete()
C. move()
D. copy
Ans:A
Which of this interface contain a unique element?
A.Map
B.Comparable
C.Set
D.List
Ans: C
Which of the below packages consists of all the classes of the Collection framework Ajava.lang
B.java.util
C.java.awt
D.java.io
Ans : B
Which class does not override the equals() method,inheriting directly from class Object?
A.java.String
B.java.Integer
C.java.StringBuffer
D.java.Character
Ans: C
scanner class comes under which package
A. java.sql
B. java.lang
C.java.util
D.java.awt
Ans : C
JVM processes on which code
A.source code
B.Byte code
C.machine code
D.native code
Ans: B
Static method must be called by A.class name
B.package name
C.object name
D.method name
Ans:A
which class is the parent of all the exceptions in Java
A.Scanner
B.Thread
C.Throwable
D.Exception
Ans:D
Which is the unchecked exception in java
A.ClassNotFoundException
B.SQLException
C.IOException
D.ArithmeticException
Ans:D
____ method of String class is used to create exact copy of heap string object into scp area A.split
B.intern
C.trim
D.substring
Ans:B
which concept in Java is used to wrap the data and provide security to the data A.Encapsulation
B.Abstraction
C.inheritance
D.polymorphism
Ans:A
Choose the correct set of wrapper classes in java
A. Integer,Char,Byte,String
B.Integer,Long,Boolean,Byte
C.Integer,Float,String,Short
D.Integer,Double,Byte,String
Ans: B
Which keyword should we used To override the property of one class into another class
A.static
B.this
C. final
D.super
Ans: D
By using ________ keyword in Java, we can call one method inside another method of same class
A.static
B.this
C. final
D.super
Ans:B
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Which statement is correct about the thread
A. On calling the thread start method a new thread gets created
B. Thread start() method can call run() internally
C. The thread run method can not be called directly to create a thread
D. All are correct
Ans:D
What is the valid declaration of float?
A.float f=1.0;
B.float f=”1.0”;
C.float f=1;
D. float f=1.0f;
Ans: D
Which of the iterators can traverse the collection in both directions? A.Enumerated Iterator
B.List Iterator
C.Map Iterator
D.Set Iterator
Ans:B
Which one of the following is Java’s reserved word?
A. main
B.run
C.implement
D.import
Ans:D
The constructor must be the same as ______ name
A.class
B.object
C.method
D.block
Ans: A
Can we override private methods in Java?
A.yes
B.no
Ans:B
break keyword used only inside
A.if statements
B.class and loops
C.switch case and loops
D.loops and if statements
Ans:C
How can we create our own immutable class
A. declaring that class as public
B. making the constructor is private
C. by declaring that class as a final
D. by creating only one constructor
Ans:C
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