String Processing

Question 1

Which deprecated class splits a String into elements but does not support enhanced for iteration?

Answer 1

StringTokenizer

Question 2

In a regular expression, which character indicates an optional subpattern that can match only once?

Answer 2

?

Question 3

What does the format parameter %s specify?

Answer 3

String conversion

Question 4

In a regular expression, which metacharacter specifies a word boundary?

Answer 4

\b

Question 5

In a regular expression, which metacharacter specifies an upper/lowercase letter or digit?

Answer 5

\w

Question 6

In a regular expression, which character indicates zero or more subpattern match?

Answer 6

*

Question 7

In a format string, what does the % character specify?

Answer 7

The beginning of a format parameter

Question 8

In a String, which character is required to escape the initial backslash for Java?

Answer 8

\

Question 9

When using manipulation methods of the StringBuffer and StringBuilder class, how is the underlying String affected?

Answer 9

The underlying String is modified.

Question 10

What does the format parameter %b specify?

Answer 10

Boolean conversion

Question 11

When using the format parameter %b, which two values will convert to false?

Answer 11

false, null

Question 12

Which String method accepts a regular expression and replacement string for each match, and returns a manipulated string?

Answer 12

replaceAll

Question 13

Which Scanner method accepts a regular expression and returns the next match found in the source line?

Answer 13

findInLine

Question 14

In a format string, what does the $ character specify?

Answer 14

the end of an argument location

Question 15

What does “3” in format string %3.4s represent

Answer 15

Minimum number of characters to output.

Question 16

What does “4” in format string %3.4s represent

Answer 16

The number of characters of the argument string to output.

Question 17

What would the following printf statement output:

System.out.printf(“<%10.4s>”,1234);

Answer 17

>

 1234<

Question 18

What would the following printf statement output:

System.out.printf(“<%-10.4s>”,1234);

Answer 18

> 1234 <

Question 19

What does format flag “-“ do?

System.out.printf(““,1234);

Answer 19

Left justifies (default is right justify)

Question 20

What does format flag “+” do?

Answer 20

Outputs a plus or minus sign for a numerical value.

Question 21

What would the following statement output?

System.out.printf(“<%0+10d>”,1);

Answer 21

> +000000001<

Question 22

Can more than one format flag be used in a format statement?

Answer 22

Yes,

System.out.printf(“>%0+10d+000000001<

Question 23

What is the output of this statement?

System.out.printf(“<%0-10d>”,1);

Answer 23

java.util.IllegalFormatFlagsException

Using “0” for zero fill and “-“ for left jistify together is not valid.

Question 24

What does format flag “0” do?

Answer 24

forces numerical values to be zero-padded (default is blank padding).

Question 25

What does format flag “,” do?

Answer 25

Comma grouping seperator for numbers > 1000

System.out.printf(“>%0+,10d,1);

Question 26

Is System.out.printf(“<%0+,10d>”,1000); a valid statement and if yes what will it output?

Answer 26

> +00001,000<

Question 27

What flag is used to output a minus character for negative numbers and a space for positive numbers?

Answer 27

Space as in

System.out.printf(“>% ,10d,-1001);

Question 28

Consider:
String nullString = null;
String ten = nullString.valueOf(10); // Line 2

Will Line 2 generate a null pointer exception?

Answer 28

No! Because valueOf is a static method so the referencetype is used not the object type. The string ten will be set to “10”.

Question 29

What are the String static methods?

Answer 29

valueOf, format, copyValueOf

Question 30

Is this following valid?

aString.format(“%s%n”,aString);

Answer 30

Yes! It will output the string followed by a