Java Strings

Strings in Java are _________.

• Mutable

• Immutable

Answer explanation

Strings in Java are immutable. When you make some changes to a string variable in Java, it actually creates a new String in the memory.

Which of the following is the incorrect way of creating a string in java?

• var hello string = "world"

• String hello = "World";

• String hello = new String("World");

• final static String hello = "World";

Answer explanation

var hello string = "world" is the incorrect way. This way of creating strings is used in GoLang, and not in Java.

What is the error in the following lines of code?

private String myMethod() {}

• String is not being returned.

• No value is being returned.

• There is no error.

Answer explanation

In the following lines of code, a string should be returned from 'myMethod'. 'No value is being returned' might confuse you, but it is a string method, so particularly String should be returned and not any value.

Create a String variable 'name' and put it equal to the value John Doe.

Which of the following will return the number of characters present in a String?

• length()

• length

• sizeOf()

• numberOfChars()

Answer explanation

Number of characters in a string means the length of the string, but length is not a property of strings in java. Instead, there is a method length. Hence, length() is correct, not length.

What will be the output of the following line of code?

• HelloWorld

• Hello World

• "Hello World"

• "HelloWorld"

Answer explanation

While printing strings, double quotes aren't printed. So "Hello World" and "HelloWorld" are cancelled. Now the trim function removes white space from starting and ending of a string, and not from center. So space between hello and world remains. There are no whitespaces on left and right, so Hello World is printed as it is.

What is the output of the following code?

• True

• False

• true

• false

Answer explanation

In java, booleans are written completely in lower case. Thus, True and False are eliminated.

Now Hello World starts with Hello and not hello (with lower case h) so output is false.

What is the output of following code?

• Llo World

• Hello World

• llo World

• llo world

What is the output of the following lines of code?

• 8

• r

• o

• IndexOutOfBoundsException in thread main

What is the output of the following code?

• HELLO WORLD

• hello world

• "HELLO WORLD"

• Hello World