1. Java String, StringBuffer and
StringBuilder
Sujit Kumar
Zenolocity LLC
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2. Mutability
• String is immutable – cannot change once it
has been created.
• StringBuffer is mutable.
• StringBuilder is mutable.

3. Thread Safety
• StringBuffer is thread-safe => all methods are
synchronized.
• StringBuilder is NOT thread-safe.
• Slight performance overhead with using
StringBuffer class as compared to using the
StringBuilder class.

4. When to use each?
• Use String if you require immutability
• Use StringBuffer if you need mutability and
thread-safety.
• Use StringBuilder if you need mutability but
no thread-safety but better performance.