Interview Question

String vs StringBuilder vs StringBuffer?

String is immutable; StringBuilder is mutable; StringBuffer is synchronized and mutable.

💡 Concept ✅ Quick Revision ☕ Java

Answer

String is immutable; StringBuilder and StringBuffer are mutable character-sequence builders. • StringBuilder is not synchronized. • StringBuffer synchronizes its methods for thread-safe individual operations. • Use StringBuilder for ordinary local concatenation loops and String when the final value should be immutable.

Example

Code

StringBuilder builder = new StringBuilder();
builder.append("Java").append(" SE");
System.out.println(builder);

Output

Java SE

Quick Revision

String is immutable; StringBuilder is mutable; StringBuffer is synchronized and mutable.

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