Simple Twisters on Java Strings

Java Stings is a relatively easy topic in Java to understand.But until you master any topic you cannot answer even the simplest questions on that topic.These twisters are interesting and will test your Strings knowledge.In the previous tutorials on Java Strings you have learned following topics:-

1.How JVM Handles Strings
2.Important Java Strings methods
3.Method Chaining in Strings

if you wish to answer the following questions i recommend you to look back the previous tutorials to make your Java String Concepts more strong.

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1.In Java Strings are immutable and Cannot be changed
a)True
b)False

2.What would be the output of following code:-

String a="abcdefgh";
a.concat(" i don't know buddy!!");
System.out.println(a);

a)abcdefgh i don't know buddy!!
b)abcdefgh
c)Compilation fails
d)Runtime Exception

3.How many Strings are created in the String constant pool upon compilation of following code segment:-

String a="abcdefgh";
a=a.concat(" i don't know buddy!!");
System.out.println(a);

a) 1
b) 2
c) 3
d) 4

4.What would be the output of following code:-

String a="abcdefgh";
a=a.concat(" i don't know buddy!!");
System.out.println(a);

a)abcdefgh i don't know buddy!!
b)abcdefgh
c)Compilation fails
d)Runtime Exception

5.What would be the output of following code segment:-

String a ="abcdefgh";
a.toString();
a.concat("Its not a joke dude!!!");
System.out.println(a.concat("Its amazing"));
System.out.println(b.toUpperCase());

a)abcdefgh Its amazing
ABCDEFGH

b)abcdefgh
ABCDEFGH

c)ABCDEFGH
d)Compilation fails

6.What would be the output of following code segment:-

String s="abcdefgh";
System.out.println(s.length);
System.out.print(s+="ijk");

a) 8abcdefgh
b) 8abcdefghijk
c) Compilation fails
d) Rintime Exception

7.What would be the output of following code segment:-

String s="abcd";
String r=s.toUpperCase().concat("efgh").replace('A','Z');
System.out.println(r);

a)abcdefgh
b)ABCDEFGH
c)Zabcdefgh
d)ZBCDEFGH


8.What happens when Strings having no reference reside in String constant pool?
(select all that apply)

a)JVM repeatedly search for Strings with no reference and sweeps them to recollect the memory in String Constant pool.
b)String continues to reside in the memory and JVM doesnot do anything.
c)JVM keeps them in constant pool for some time then eliminates them.
d)The String Constant pool memory Overflows.

Useful Links:-

Java Interview questions on Utilities and Strings
Java Interview Questions
Best Java Interview Questions
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