Java Reference
In-Depth Information
c. s1 == s4
d. s1.equals(s3)
e. s1.equals(s4)
f.
"Welcome to Java"
.replace(
"Java"
,
"HTML"
)
g. s1.replace(
'o'
,
'T'
)
h. s1.replaceAll(
"o"
,
"T"
)
i. s1.repla
ceFirst(
"o"
,
"T"
)
j.
s1.toCharArray()
10.16
To create the string
Welcome to Java
, you may use a statement like this:
String s
=
"Welcome to Java"
;
or:
String s
=
new
String(
"Welcome to Java"
);
Which one is better? Why?
10.17
What is the output of the following code?
String s1 =
"Welcome to Java"
;
String s2 = s1.replace(
"o"
,
"abc"
);
System.out.println(s1);
System.out.println(s2);
10.18
Let
s1
be
"Welcome"
and
s2
be
"welcome"
. Write the code for the following
statements:
a. Replace all occurrences of the character
e
with
E
in
s1
and assign the new string
to
s2
.
b. Split
Welcome to Java and HTML
into an array
tokens
delimited by a space
and assign the first two tokens into
s1
and
s2
.
10.19
Does any method in the
String
class change the contents of the string?
10.20
Suppose string
s
is created using
new String()
; what is
s.length()
?
10.21
How do you convert a
char
, an array of characters, or a number to a string?
10.22
Why does the following code cause a
NullPointerException
?
1
public class
Test {
2
private
String text;
3
4
public
Test(String s) {
5
String text = s;
6 }
7
8
public static void
main(String[] args) {
9 Test test =
new
Test(
"ABC"
);
10 System.out.println(test.text.toLowerCase());
11 }
12 }
10.23
What is wrong in the following program?
1
public class
Test {
2 String text;
3
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