Why is String immutable in Java?

Reasons for Immutability:

1. String Pool: Efficient space management by sharing string literals. If strings were mutable, changing one would affect all other shared references.
2. Security: Strings are frequently used as parameters for network connections, database URLs, and file paths. Immutability ensures these cannot be changed mid-process.
3. Thread Safety: Immutable objects are inherently thread-safe and can be shared across threads without synchronization.
4. Caching Hashcode: The hashcode is cached during creation, making strings ideal keys for HashMaps.