java important input output problems

Question 01

What is the output of the following:

System.out.println("1" + 1);

System.out.println('1' + 1);

System.out.println("1" + 1 + 1);

System.out.println("1" + (1 + 1));

System.out.println('1' + 1 + 1);

Output

Output is 11

                  50

                   111

                    12

                   51

Question 02

What is the output of the following:

System.out.println("1" + 1+3);

System.out.println('1' + 1*3);

System.out.println("1" + 1 *4+4+ 1);

System.out.println("1" + 4+(1 + 1));

System.out.println('1' + (1+3) + 1);

 }

Output

Output is

113

52

1441

142

54

java methods

Question 30

What is equals()

 Ans

It compare two strings and it is case sensitive

Question 31

What is equalsIgnoreCase()

 Ans

This function compare two strings but it is not case sensitive.

Question 32

Give example of equals()

 Ans

String s1="this4is4my4book";

String s2="this4is4my4book";

String s3="lkajfslagj;fklgja";

System.out.println(s1.equals(s2));  //true

 System.out.println(s3.equals(s2));  //false

Question 33

Give example of equalsIgnoreCase()

 Ans

String s1="thIs4is4My4book";

String s2="This4is4my4Book";

String s3="lkajfslagj;fklgja";

System.out.println(s1.equalsIgnoreCase(s2));  //true

 System.out.println(s3.equals(s2));               // false

java theory

Question 22

What is toLowerCase();

Ans

It convert upper case into lower case.

 Question 23

Give  example of  toLowerCase()

Ans

Example      Charater.toLowerCase(P)   it returns  p

Question 24

What is trim()

Ans

The void space is removed from both sides using trim().

Question 25

Give example of trim()

Ans

It "\t Good Night \n".trim() returns a new string Good Night.

Question 26

What is length()

Ans

It is used to calculate to number of character in a string

Question 27

Give example of  length

Ans

String d=”This is my book and”,

System.out.println(d.length());    it returns 19

Question 28

What is indexOf()

Ans

It is used to check the index number of character

 Question 29

Give example indexOf()

Ans

"Welcome to Java".indexOf('o') returns 4.

java important theory problems

Question 16

What is isUpperCase();

Ans

It work on single character. This function return true or false. If user enter character in upper case returns true otherwise it returns false

Question 17

Give example of isUpperCase();

Ans

Example       Character.isUpperCase(A)    returns true  Character.isUpperCase(s)

Returns false.

Question 18

What is isLowerCase();

Ans

It work on single character. This function return true or false. If user enter character in lower case returns true otherwise it returns false

Question 19

Give examples of  isLowercase()

Ans

Example       Character.isLowerCase(s)    returns true  Character.isLowerCase(A)

Returns false.

Question 20

What is toUpperCase();

Ans

It convert lowercase into upper case.

Question 21

Give example of toUpperCase();

Ans

Example      Charater.toUpperCase(a)   it returns  A