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javastring-concatenation

Java multiline string formation

I'm by no means a java programmer, so this may seem pretty basic.

Which of these are 'better' when you want to keep your code lines short.

String str = "First part of a string.";
str += " Second part of string.";

or 

String str = "First part of string." +
" Second part of string."

I guess my question is do both the += and + make a new String object? If they do then neither really are better, it would just be a matter of preference. The example I gave would be a good example of real world use. I don't want a comparison of doing a concatenation 3 times to 1000 times with either method.

Thanks

Solution

  • I prefer the 2nd method. The reason is that the compiler will likely combine the result of the concatenation into a single string at compile time while the 1st method may be done at run-time (depending on the actual implemention.) It's a small thing unless you're doing something millions of times, however.