Java – use characters instead of strings for single character values in StringBuffer append

I am passing the PMD rule appendcharacterwithchar It says avoid in StringBuffer Append concatenates characters into strings

StringBuffer sb = new StringBuffer();
  // Avoid this
  sb.append("a");

  // use instead something like this
  StringBuffer sb = new StringBuffer();
  sb.append('a');

Do I really need this PMD rule? How different is the performance between the following two pieces of code?

String text = new StringBuffer().append("some string").append('c').toString();

String text = new StringBuffer().append("some string").append("c").toString();

Solution

Appending a character as a char will always be faster than appending it as a string

But are performance differences important? If you only do it once, it won't If it repeats its body a million times in a cycle, yes, this may be important

If you already have this character at compile time, just take it as a character If it's stored in a variable of type string, don't bother accessing it Use string Charat (0) or some other methods, just append string

Note:

Like StringBuilder class to StringBuffer StringBuilder is faster because its methods are out of sync (you don't need it in most cases)

Side note 2#

This does not compile:

String text = new StringBuffer().append("some string").append('c');

Append() returns StringBuffer for linking You need to call tostring():

String text = new StringBuffer().append("some string").append('c').toString();