String creation in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new String with the value "Hello".

Java

String greeting = new String([1]);

Drag options to blanks, or click blank then click option'

A'Hello'

BHello

C"Hello"

Dhello

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes instead of double quotes for strings.

Not using quotes at all.

The correct way to create a String with the value "Hello" is to use double quotes around the text.

2fill in blank

medium

Complete the code to create a String variable named name with the value "Alice".

Java

String name = [1];

Drag options to blanks, or click blank then click option'

Anew String(Alice)

BAlice

C'Alice'

D"Alice"

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes instead of double quotes.

Not using quotes at all.

To assign a string literal to a variable, use double quotes around the text.

3fill in blank

hard

Fix the error in the code to correctly create a String with the text "Java".

Java

String lang = new String([1]);

Drag options to blanks, or click blank then click option'

Ajava

B"Java"

C'Java'

DJava

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes which are for characters, not strings.

Not using quotes at all.

The string must be enclosed in double quotes to be valid in Java.

4fill in blank

hard

Fill both blanks to create a String variable called message with the value "Welcome".

Java

String [1] = new [2]("Welcome");

Drag options to blanks, or click blank then click option'

Amessage

Bmsg

CString

Dstring

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'string' instead of 'String'.

Using an invalid variable name.

The variable name should be 'message' and the class name is 'String' with uppercase S.

5fill in blank

hard

Fill all three blanks to create a String variable named text with the value "Code" using the constructor.

Java

String [1] = new [2]([3]);

Drag options to blanks, or click blank then click option'

Atext

BString

C"Code"

Dcode

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'string' instead of 'String'.

Not using quotes around the string literal.

The variable name is 'text', the class is 'String', and the string literal must be in double quotes.

Practice

1. Which of the following is the correct way to create a string variable in Java?

easy

A. String greeting = "Hello";

B. string greeting = 'Hello';

C. String greeting = Hello;

D. String greeting = "Hello"

Solution

1. Step 1: Check the data type and quotes

   Java strings use the class String with a capital S and text must be in double quotes.

2. Step 2: Validate syntax correctness

   String greeting = "Hello"; uses correct capitalization, double quotes, and ends with a semicolon.

3. Final Answer:

   String greeting = "Hello"; -> Option A

4. Quick Check:

   String creation uses String and double quotes [OK]

Hint: Use capital S in String and double quotes for text [OK]

Common Mistakes:

• Using single quotes instead of double quotes
• Using lowercase 'string' instead of 'String'
• Missing semicolon at the end

2. Which of the following lines will cause a syntax error in Java?

easy

A. String name = "Alice";

B. String name = 'Alice';

C. String name = "Bob";

D. String name = "Charlie";

Solution

1. Step 1: Identify correct string literal syntax

   Java strings must be enclosed in double quotes, not single quotes.

2. Step 2: Check each option

   String name = 'Alice'; uses single quotes which is invalid for strings in Java, causing a syntax error.

3. Final Answer:

   String name = 'Alice'; -> Option B

4. Quick Check:

   Strings need double quotes, single quotes cause syntax error [OK]

Hint: Remember: Java strings use double quotes only [OK]

Common Mistakes:

• Using single quotes for strings
• Confusing char literals with strings
• Missing semicolon

3. What will be the output of the following code?

String first = "Good";
String second = "Morning";
System.out.println(first + " " + second);

medium

A. GoodMorning

B. Good+Morning

C. Good Morning

D. gninroM dooG

Solution

1. Step 1: Understand string concatenation

   The + operator joins strings. Here, first + " " + second adds a space between words.

2. Step 2: Combine the strings

   "Good" + " " + "Morning" results in "Good Morning" with a space.

3. Final Answer:

   Good Morning -> Option C

4. Quick Check:

   + joins strings including spaces [OK]

Hint: Use + with " " to add spaces between words [OK]

Common Mistakes:

• Forgetting to add space between words
• Using + without quotes for space
• Expecting + to print plus sign

4. Find the error in the following code snippet:

String text = "Hello"
System.out.println(text);

medium

A. System.out.println syntax is wrong

B. Incorrect string quotes

C. Variable name is invalid

D. Missing semicolon after string assignment

Solution

1. Step 1: Check string assignment line

   The line ends without a semicolon, which is required in Java statements.

2. Step 2: Verify other lines

   Quotes are correct, variable name is valid, and print statement syntax is correct.

3. Final Answer:

   Missing semicolon after string assignment -> Option D

4. Quick Check:

   Every statement must end with a semicolon [OK]

Hint: Always end Java statements with a semicolon [OK]

Common Mistakes:

• Omitting semicolon at end of statement
• Confusing quotes with apostrophes
• Misnaming variables

5. You want to create a string variable that holds the full name by combining first and last names with a space. Which code correctly does this?

hard

A. String fullName = firstName + " " + lastName;

B. String fullName = firstName + lastName;

C. String fullName = firstName.concat(lastName);

D. String fullName = firstName - lastName;

Solution

1. Step 1: Understand string concatenation with space

   To add a space between first and last names, include " " between them.

2. Step 2: Check each option

   String fullName = firstName + " " + lastName; correctly uses + operator with a space string. String fullName = firstName + lastName; misses space, C concatenates without space, D uses invalid operator.

3. Final Answer:

   String fullName = firstName + " " + lastName; -> Option A

4. Quick Check:

   Use + " " + to add space between strings [OK]

Hint: Add " " between strings to insert space [OK]

Common Mistakes:

• Forgetting space between names
• Using invalid operators like -
• Using concat() without space