JavaStrings in Java

String vs char[] in Java

Understand the difference between String and char[] in Java, focusing on mutability, security, memory usage, and best practices.

String vs char [ ] in JavaLink to this section

In Java, text data can be stored using both String and char[]. Choosing the right option is important for performance and security.

Although they appear similar, their behavior in memory and mutability is very different.

Using StringLink to this section

A String object is immutable, meaning its content cannot be changed once created.

warning

Using String for sensitive data like passwords can be unsafe because the data stays in memory.

Using char[]Link to this section

A char[] is mutable, meaning its contents can be modified or cleared manually.

tip

char[] is preferred for storing sensitive information like passwords.

Security PerspectiveLink to this section

Strings are stored in the String Constant Pool, which may remain in memory longer than expected.

char[] allows explicit clearing of data after use.

note

Java APIs such as authentication frameworks prefer char[] for credentials.

Performance and MemoryLink to this section

String objects create new instances for every modification, increasing memory usage.

char[] allows in-place modification, reducing memory overhead.

String vs char[]
Question 1 of 5

Which is mutable in Java?

String vs char[]

medium
  1. Store a password using String and explain the security risk.
  2. Rewrite the same logic using char[] and clear the array after use.
  3. Compare memory behavior of String and char[] with frequent updates.
  4. Explain why String is still widely used despite security concerns.
  5. Identify real-world scenarios where char[] is preferred.