Explain the concept of the string pool in Java and its purpose.

The String Pool in Java is a special area in memory where unique string literals are stored. When you create a string as a literal, the JVM places it in the string pool to avoid duplicating identical strings and to save memory.

For example, if there are two strings with the same value in the code, both will refer to the same object in the pool, rather than creating two separate objects.

Example:

String s1 = "hello";
String s2 = "hello";
System.out.println(s1 == s2); // true, both references point to the same object in the pool

String s3 = new String("hello");
System.out.println(s1 == s3); // false, s3 is a new object outside the pool

The purpose of the string pool is to improve performance and reduce memory consumption by reusing immutable strings.