As of Java 8, the default garbage collection algorithm was the parallel garbage collector. Java 8 was released with some improvements to the G1 garbage collection system. One of these improvements was the ability to use the following command-line option to optimize the heap memory by removing duplicative string values:

-XX:+UseStringDeduplication

The G1 garbage collector can view the character arrays when it sees a string. It then takes the value and stores it with a new, weak reference to the character array. If the G1 garbage collector finds a string with the same hash code, it will compare the two strings with a character-by-character review. If a match is found, both strings end up pointing to the same character array. Specifically, the first string will point to the character array of the second string.

This method can require substantial processing overhead and should only be used if deemed beneficial or absolutely necessary.