What is String interning and the String Pool?

String Pool:

A special storage area in the JVM Metaspace (formerly PermGen) that stores a single copy of each unique string literal.

String Interning:

• When a literal is used ("abc"), the JVM automatically checks the pool.
• If it exists, the reference is returned. If not, the string is added to the pool.
• s.intern(): Manually ensures that if the pool already contains a string equal to this String object, the pool's reference is returned.