String creation in Java - Cheat Sheet & Quick Revision

overview

Recall & Review

beginner

What is the simplest way to create a String in Java?

You can create a String by enclosing text in double quotes, like String s = "Hello";. This is called a string literal.

intermediate

What does new String("text") do compared to a string literal?

It creates a new String object in memory, even if the same text exists as a literal. This is less efficient than using literals directly.

beginner

Can Strings in Java be changed after creation?

No, Strings are immutable. Once created, their content cannot be changed. Any modification creates a new String object.

intermediate

How does Java optimize String creation with literals?

Java uses a String pool to store literals. If a literal already exists, Java reuses it instead of creating a new object.

intermediate

What is the difference between String s = "abc"; and String s = new String("abc");?

The first uses the String pool and reuses the literal if available. The second always creates a new String object in memory.

Which of these creates a String literal in Java?

A String s = StringBuilder.append("Hello");

B String s = new String("Hello");

C char[] s = {'H','e','l','l','o'};

D String s = "Hello";

What happens when you create a String with new String("abc")?

A It creates a new String object in memory.

B It creates a StringBuilder object.

C It reuses an existing String from the pool.

D It throws an error.

Are Java Strings mutable (can they be changed after creation)?

A No, Strings are immutable.

B Yes, you can change characters inside a String.

C Only if you use StringBuilder.

D Only if you use new String().

What is the purpose of the String pool in Java?

A To store all String objects created with new.

B To store unique String literals for reuse.

C To speed up String concatenation.

D To convert Strings to char arrays.

Which is more memory efficient for creating Strings?

A Using char arrays

B Using new String("text")

C Using String literals like "text"

D Using StringBuilder

Explain how Java creates and stores Strings using literals and the new keyword.

Why are Java Strings immutable and what does that mean for modifying text?