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3 Ways to Diff Java Code in IntelliJ [Video]

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3 Ways to Diff Java Code in IntelliJ [Video]

IntelliJ has an inbuilt diff tool which you can use to compare files, classes or code with the clipboard. Just right-click and choose Compare.

· Java Zone ·
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I was busy refactoring code in RestMud this morning because I want to try and open source the basic game engine, and then later the Web/REST API, but I want to tidy up the code a little first.

I've been working through the code:

  • Moving classes into new packages
  • Splitting classes to make code clearer and easier to manage
  • New classes make code easier to test

And the more I tidy it up in general, the easier it is to spot smaller problems of code duplication.

Sometimes I fix the duplication by:

  • Extracting code into a new class and delegating functionality off to the class
  • Extracting code into private methods

IntelliJ has an incredibly useful piece functionality to help with that in the form of the Compare Tool.

The Compare Tool

The compare tool is a built-in diff tool.

I can use it in three different ways:

  • Right-click on a file and "Compare" then choose a file on my hard drive to compare with
  • Select two classes in the project view and right click to "Compare"
  • Select code, add it into the clipboard, then highlight a different block of code and "Compare with Clipboard"

They all use the same 'diff' view, which is much easier than:

  • Using a separate tool like WinMerge to compare files outside of the IDE.
  • Splitting the window and visually trying to compare code

I show all three approaches in this short YouTube video.

java ,diff ,intellij ,compare ,tutorial ,refactoring

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