Prac

Question 1

Super class of exception and error

Answer 1

Throwable Class

Question 2

Graphics class belongs to which class

Answer 2

AWT

Question 3

Awt full form

Answer 3

Abstract Window Toolkit

Question 4

Import statement used for

Answer 4

import statement is used to access buit-in java packages which contains a set of particular classes.

Question 5

Int data type ka size

Answer 5

4

Question 6

New keyword ka use

Answer 6

New keyword is used in new operator to create a new object.

Question 7

Static and non static method me diff..and unko call kerne ka difference

Answer 7

Static methods are methods which do not have any relationship with objects in the class , they exist independently and the class may not have an object at all.
Any method that has a relationship with the object is called non-static method.

Question 8

Inheritance kya hai

Answer 8

In Java, an object can acquire the behavior and properties from another object. This is also called a parent-child relationship. Morover, the child may even have behavior and properties of its own.

Question 9

Array kaise declare kerna

Answer 9

Datatype [ ] name;

Question 10

Abstract method kya hai..and u ll know its abstract class

Answer 10

Abstract class is a class that cant be used to create objects. Abstarct method is a method which is not implemented.

Question 11

Diff between string buffer and string class

Answer 11

String class is used to store data sequentially and it is immutable i.e. That once the memory is assigned it cant be diminished or changed.
String buffer however is also used to store data sequentially but is mutable i.e. the memory can be deleted or modified

Question 12

Enhance for loop

Answer 12

Enhanced for loop is a type of for loop that is used to iterate through a collection of data in first to last order and the user doesnt need to know the crent value of the index. It does so by traversing the data.

Question 13

User defined data types in java

Answer 13

User defined data types are the data types that are created by the user in Java

Question 14

Command line arguments

Answer 14

Command Line arguments are the arguments that are passed at the command line during the execution of a program.

Question 15

Showinputdialog box kya return kerta hai

Answer 15

String

Question 16

than what is array fir

Answer 16

Array is used to store similar type of data in Java but has a limit to it. It is further o f 2 types :-
Single-dimensional array
Multi-dimensional Array

Question 17

super class of exception & error

Answer 17

Throwable Class

Question 18

graphics kiska part h?

Answer 18

Abstract window Toolkit

Question 19

haan applet kiska part h

Answer 19

Java.Applet

Question 20

difference print & println

Answer 20

Print() prints output isn the same line

Println() provides output in the next line

Question 21

Console application

Answer 21

The console applicaton is used to get input from Console. It is used to read texts and passwords from the user.

Question 22

Native method

Answer 22

A native method is a method in java whose implementation is written in a language other than java.

Question 23

Applet

Answer 23

An applet is a special type of program that is embedded in a webpage to generate dynamic content. It works on the client side.

Question 24

AWT

Answer 24

Abstract Window Toolkit. It is a platform dependent API that is used to create GUI for Java progs.

Question 25

Difference between length and length()

Answer 25

length is used to find out length of an array and does so directly length() is used to find out length of a string and it does so by invoking a method rather than doing it directly

Question 26

Equals()

Answer 26

Equals() is used to compare two strings in Java and returns true if the values are the same, false otherwise.

Question 27

Short Ka bytes

Answer 27

2

Question 28

which is the parent class for all the wrapper class

Answer 28

Number for int,long,short and object for char and boolean

Question 29

COncrete method

Answer 29

A method that is not abstarct is caleed concrete method i.e. method definition is provided in the same class as declaration.

Question 30

Method overloading

Answer 30

A class in java may have multiple methods with the same name and return type,but with different number of arguments or datatype of arguments

Question 31

Method Overriding

Answer 31

When A child class has the same method and parameters as Parent Class, it is called Method Overriding.

Question 32

Array class belongs to which package

Answer 32

Java.util

Question 33

Heart and soul of thread

Answer 33

Run()

Question 34

Multiple inheritance is possible or not

Answer 34

no

Question 35

1. array name contains what?

Answer 35

It contains the reference to the memory address where the value is stored

Question 36

3. difference abstract class and interface?

Answer 36

Abstract class provides partial abstarction, uses extends, can have constructor, can inherit another class and implement an interface, Interface provides complete abstraction, uses implements, cant have constructors, and can only inherit another interface.

Question 37

5. Instanceof operator?

Answer 37

The instanceof() operator is used to determine whethen object belongs to a particular class or not and returns true or false accordingly.

Question 38

6. What does ShowConfirm dailog box returns?

Answer 38

int

Question 39

7. What does ShowInput dailog box returns?

Answer 39

str

Question 40

8. What does ShowMessage dailog box returns?

Answer 40

str

Question 41

10. Why we use object of graphic class in paint method()?

Answer 41

Graphic class is an abstract class and paint () is a method which contains shapes lines etc but whose default version does nothing. So paint () is called to help draw lines, shapes etc.

Question 42

11. printStackTrace()?

Answer 42

PRINTSTACKTRACE() helps us to trace the trail of a method which threw an exception by displaying a stack of called methods.

Question 43

12. thread life cycle methods?

Answer 43

newborn, runnable, running, blocked, dead states.

Question 44

applet lifecycle methods

Answer 44

born, running, idle , destroyed

Question 45

14. diff setcolor setbackgroundcolor?

Answer 45

setcolor is used to set the color of a particular shape, while setbackgroundcolor is used to the bachgroundcolor of the applet.

Question 46

21. CharAt?

Answer 46

Returns the character at specified index

Question 47

22. Wrapper class belong to which package?

Answer 47

Java.lang

Question 48

24. Method which set the background color in graphics?

Answer 48

setBackground COlor

Question 49

25. Set font() method?

Answer 49

SETS THE FONT OF TEXT IN APPLET

Question 50

27. protected class?

Answer 50

A class that is accessible inside the package and outside the package using child class

Question 51

30. What is package?

Answer 51

A named collection of classes and interfaces

Question 52

1. What is package?

Answer 52

javax.swing.joptionpane()

Question 53

2. Default package imported in java?

Answer 53

Java.lang

Question 54

5. Why we specify joptionpane in front of showinputdialog?

Answer 54

Joptionpane is the class name that allows us to produce the dialog box

Question 55

8. What is filloval method?

Answer 55

It is used to draw an oval and fill it witha particular color

Question 56

10. default constructor

Answer 56

When a class has no constructor, the compiler automatically creates a default constructor

Question 57

isAlive() method?

Answer 57

This method tests whether the thred is alive

Question 58

currentThread()

Answer 58

Returns reference to currently implementing thread object

Question 59

7. Why we use runnable interface?

Answer 59

It should be used by any class whose instances are intended to be used by a thread.