StringBuffer append("")

Question

I'm currentlly refactoring an application using a lot of this:

StringBuffer buff1 = new StringBuffer("");

buff1.append("some value A");
buff1.append("");
buff1.append("some value B");

The coder that made those code lines didn't seems to be an idiot, is there any reasons I can't see to use the append("") to a StringBuffer?

Answer 1

No you don't need that append(""). You also do not need to initialize the StringBuffer with a String. new StringBuffer(); will work fine.

Answer 2

Nope.

And given that they're hardcoded strings, it'd be identical to write

buff1 = new StringBuffer("some value Asome value B");

BTW, it's a bit more efficient to use a StringBuilder rather than a StringBuffer (and the API is identical).

Answer 3

The only reason I can think of why he'd do that is readability (though even that seems a bit strange).

Answer 4

It's very likely that code was generated by some refactoring tool and the coder wasn't bothered to remove the redundant lines.

Answer 5

If there are no further appends made to the StringBuffer the code should be rewritten as

String buff1 = "some value some value B";

This is more concise, more readable and safer than:

StringBuffer buff1 = new StringBuffer("");

buff1.append("some value A");
buff1.append("some value B");

I say 'safer' because a String is immutable and a StringBuffer is immutable, so there's no risk of the String accidentally being changed after construction.

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Aside

It's a common misconception that "concatenating Strings in Java is bad". While it's true that you shouldn't write code like this

String buff1 = "foo";    
buff1 += "some value A";
buff1 += "some value B";

It's perfectly acceptable to write code like this:

String buff1 = "foo" + "some value A" + "some value B";

when the concatenation is performed in a single statement the code will be optimized to:

String buff1 = "foo some value A some value B";

Answer 6

He probably meant to put buff1.append(" ");. Just my take.