Read full article from What is Java String Pool?
String Pool is possible only because String is immutable in Java and it’s implementation of String interning concept. String pool is also example of Flyweight design pattern.
String pool helps in saving a lot of space for Java Runtime although it takes more time to create the String.
When we use double quotes to create a String, it first looks for String with same value in the String pool, if found it just returns the reference else it creates a new String in the pool and then returns the reference.
However using new operator, we force String class to create a new String object in heap space. We can use
Read full article from What is Java String Pool?intern() method to put it into the pool or refer to other String object from string pool having same value.