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Eclipse: Catch Those Spelling Errors

At 11:36 PM on Feb 24, 2005, R.J. Lorimer wrote:

Ahh, spelling errors. I think we all make them - I know I do anyway. After typing these tips on a near daily basis I've begun to recognize that no matter how good you think you are at spelling, stupid mistakes show up, and a lot of times you get a bad spelling habit stuck in your head and continually put too many c's in necessary or something. I would be surprised if a spelling error didn't find its way in to this very tip, as I'm usually too lazy to put a lot of effort into spell checking these .

Spelling errors in documentation can mean the difference between life and death. Really?! No... not really - but spelling is important. Bugs are opened in large frameworks when spelling and grammatical errors are in the documentation. Really, it happens! In addition, people immediately take you more seriously when you spend the time to ensure that your spelling is accurate. Finally, it is definitely possible that spelling errors can convey a different meaning than intended. (Deprecate and Depreciate anyone?)

Thankfully, Eclipse has a little hidden gem that makes quick work of spelling errors. The spelling support in Eclipse has actually been around for a while now (if I'm not mistaken, it was enabled in 3.0), and recently (3.1 M4) it was enabled in the properties file editor in addition to the already supported Java editor. So, how do you enable it?

Well, the first step is to find the preference for it. That's a relatively simple process as I already know, and I am going to tell you - just go to Window->Preferences->Editors[+]->Text Editors[+]->Spelling and check Enable Spelling .

Oops, wait a minute... it has a section to provide a 'User defined dictionary'. Is this mandatory? What format does it need to be in? Do we have to type all the words by hand? This could take a while! For spell checking to work, it is currently mandatory for you to provide a dictionary. Thankfully it's not that hard to find a word-list Eclipse can use. Eclipse supports a fairly standard one-word-per-line format for the 'dictionary' file, so we just have to find one of those. The best branching off point for that is probably Kevin's Word List on Sourceforge.net . Seem too hard? Ok, fair enough. I've compiled my own word list off of an amalgum of lists (I honestly can't remember which ones, otherwise I would be sure to give credit where credit is due), and I have uploaded it here . Fair warning! This file is substantial in size - so substantial that I couldn't attach it to this message in the conventional Javalobby 'Attach File' way (around 1.5 megabytes).

Ok, so now let's enable our spell-checking. I like to drop the dictionary file in the folder with my Eclipse installation, and then reference it in the preferences, as seen here:

Then all you have to do is use it. Spell checking shows up in one of two ways - first as squiggly warnings in your documentation and strings, and second as a preemptive auto-complete for content assist (assuming you have enabled that option in the advanced section seen in the screenshot above). Here is what the spelling error marker looks like (and what happens when I press Ctrl+1 with my cursor adjacent to the error):

Here is what it looks like using the auto-complete feature (Ctrl+Space):

Unfortunately, spelling support still needs a little work in some areas; it is no panacea. So, what would I like to see in the future? For one thing, there is no way yet to control what elements are spell-checked, and which ones aren't. What I mean by that is whether javadocs, regular comments, string literals, and/or type/method/field names are spell-checked. Currently all documentation and string literals are checked, but that's it. Frankly, my string literals need checking less often than my types and fields and methods - and in my string literals, it is more often the spell-checker would be wrong. In addition, the algorithm used for finding words of a closest match doesn't always seem the most appropriate - when using the word-list for auto-complete, if I were to type 'spell' and then press Ctrl+Space, I would like 'spelling' come up in the list before 'spew' - since that is the main benefit of an auto-complete feature - completing the word!