When comparing Kdiff3 vs Intellij IDEA, the Slant community recommends Kdiff3 for most people. In the question“What are the best free 3-way merge tools for Windows?” Kdiff3 is ranked 1st while Intellij IDEA is ranked 7th. The most important reason people chose Kdiff3 is:
For modern version control systems, 3way merge support is a basic requirement, but many other open source diff viewers do not adequately handle 3way merges.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Supports 3 way merges
For modern version control systems, 3way merge support is a basic requirement, but many other open source diff viewers do not adequately handle 3way merges.
Pro Free and open source
KDiff3 is completely free to download and use. It's also open source released under the GPL.
Pro Can compare directories
It is able to compare whole directory trees.
Pro Supports editing files directly
In addition to comparing two files it also allows you to edit the merge result right in place.
Pro Diff by character not by lines
On comparing two files, difference is shown by characters; not by lines.
Pro The UI is customizable
Allow customizing colors regardless of user/system theme.
Pro Supports manual code aligning
With selecting code in one window and hitting Ctrl+Y, then selecting some other code in second window and also hitting Ctrl+Y you can manually align the code.
Pro Preprocessing before calculating differences
There are options that may pre-process compared files before Kdiff3 actually do a comparison - to ignore for example automatically generated dates and/or revision numbers added by commit hooks.
Pro Context menu shortcut
You can right-click a folder/file and the options:
- Save <file> for later
- Compare with
will be available, making launching KDiff3 really convenient.
Pro Free version available
There is a free community edition (open source) and an ultimate edition, which you can compare here.
The ultimate edition is available for free for one year for students but must be registered through an .edu e-mail account.
Pro Fast and smart contextual assistance
Uses a fast indexing technique to provide contextual hints (auto-completion, available object members, import suggestions).
On-the-fly code analysis to detect errors and propose refactorization.
Pro Intuitive and slick UI
IDEA has a clean, intuitive interface with some customization available (such as the Darcula theme).
Pro Stable and robust
IntelliJ IDEA hardly ever crashes or has any issues that plague other Java IDEs like file corruption or slowness.
Pro Support for many languages
IntelliJ supports many languages besides Java, some of these are: golang, Scala, Clojure, Groovy, Bash, etc...
Pro Smart refactorings
IDEA places an emphasis in safe refactoring, offering a variety of features to make this possible for a variety of languages.
These features include safe delete, type migration and replacing method code duplicates.
Pro Lots of plugins
Many plugins are available for almost any task a developer may need to cover. Plugins are developed by Jetbrains themselves or by 3rd parties through the SDK available for writing them.
Pro Android support, JavaEE support, etc
A very complete development environment support.
Pro Clear and detailed documentation
The documentation is exhaustive, easy to navigate, and clearly worded.
Pro Very powerful debugger
With ability to step into a certain part of a large method invocation (Shift+F7), drop frame, executing code snippets, showing method return values, etc.
Pro Many convenient features
These simplify the daily work, e.g. copy/cut a whole line without the need to select it.
Cons
Con Cannot do inline diffs
Comparison of 2 files is always side-by-side and there's no option for inline views. Overall a rather poor and confusing UI in general.
Con Confusing GUI
4 sub-windows (when you really only need 3), a lot of different colors and even more confusing result-window. No links what has changed between versions and and the result. It clearly shows it's dated or rather outdated. Great if you ever need to do a command line merge, otherwise it sucks.
Con No precise editing of the compared files
Precise work line-after-line is not possible. Only a version after the automated merge-step is editable, but not the two files separately.
Con No longer supported by Homebrew for MacOS
Cannot be installed easily on Mac as of Aug 2019.
Con Problems when files have different number of lines
For example, if you add 3 lines: A, B and C locally but on the other change there are only A and C, Kdiff3 will work out that A was added, then it says that B conflicts with C but adds C again anyway.
Con Slow for large files
Con No image compare
Compare is text based.
Con Bugs are not solved as often as they should
They are more interested in adding new features or issuing new versions than solving bugs.
Con Somewhat expensive
IntelliJ IDEA is fairly expensive, with a pricetag of $149/year.
However there is a free community edition available.
Con Built with closed source components
The version with full features is not opensource. Parts of the code are under apache licence though.
Con Lack of plugins
IntelliJ supports a very small amount of plugins. Althrough thesse are 'quality approved', many features are missing and can't be implemented because of that.
Con Standard hotkeys behave differently
Seems like hotkeys assignment in Idea has no logical consistency.
Like «F3» is usually next match, «Ctrl+W» - close tab, etc — they map to some different action by default.
There is a good effort in making the IDE friendly for immigrants from other products: there are options to use hotkeys from Eclipse, and even emacs. But these mappings are very incomplete. And help pages do not take this remapping into account, rather mentioning the standard hotkeys.
So, people coming from other IDEs/editors are doomed to using mouse and context menus (which are rather big and complex).