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.
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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.
Published at DZone with permission of Alan Richardson, DZone MVB. See the original article here.
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