What is the difference between a String and a Character Array?

Difficulty: 4/10

immutability, memory representation, performance

String vs Character Array

A character array is a mutable sequence of characters, while a String is a higher-level string abstraction whose behavior depends on the programming language. In Java, for example, String is immutable, whereas char[] is mutable.

1
A String provides higher-level operations such as searching, slicing, comparison, and concatenation.
2
A character array provides direct mutable access to individual characters.
3
Java String objects are immutable.
4
A char[] can be modified after creation.
5
Character arrays can sometimes be preferable when sensitive character data must be explicitly cleared from memory, although memory clearing has platform-specific limitations.

Scenario Questions

0-2 years experience

2-5 years experience

1Your team added a feature that builds a large JSON payload by concatenating strings. Performance degrades. Explain how using a char[] or StringBuilder could help, and what the trade‑offs are.

Follow-up Questions