Under what circumstances is it better to use the + operator to concatenate strings than to invoke the Append method of the Stringbuffer/stringbuilder object?

Once a string is assigned or instantiated, it cannot be changed, and if a new value is given it will reopen the memory address for storage.

While the StringBuffer class uses methods such as append and insert to change the string value, it simply makes continuous operations on the memory address stored by the original object, reducing the cost of the resource.

If you have a large number of operations that require string concatenation, it is best to use StringBuffer or StringBuilder.

is a small number of strings can be used +

Under what circumstances is it better to use the + operator to concatenate strings than to invoke the Append method of the Stringbuffer/stringbuilder object?