Understanding Different Approaches for Concatenating Strings in Java


Hello, fellow developers!

Today, I came across an interesting situation while working on my Java code. I had a simple line of code where I wanted to concatenate some strings, like this:

javaCopy code
String thing = "Something"; thing += " something else" + " and more.";

To my surprise, IntelliJ IDEA suggested four alternative ways to achieve the same result:

  1. Using String.format()
  2. Using StringBuilder.append()
  3. Using java.text.MessageFormat.format()
  4. Replacing += with =

I'm curious to know why IntelliJ IDEA offered these alternatives and whether there's anything inherently wrong with using += for string concatenation.

Could anyone kindly explain the differences between these approaches and why one might be preferred over the others in certain situations? I'm keen to understand the performance, readability, and best practices associated with each option.

Looking forward to your insights and learning together!

Thank you in advance for your help.

Happy coding!

MyLabCorp Portal


Hello! There's nothing wrong with `!=`.

By default, IDEA will mark supposed invalid code with a red highlight, and an erroneous code with a yellow one. Checking your sample on 2023.1.4 with default settings, there's no highlight on strings.

These four suggestions are intentions which are available to the user and were provided or upon request, or adopting specific code styles or some best practices which can vary per person or per company. We trying not to impose any code style or choices from our side, so we're providing different options.

Sometimes you can even see opposite intentions:

Both are valid in general.

Intentions can be turned off/on in "Preferences | Editor | Intentions" if needed, or disabled on the fly.