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    <p>Consider the split expression <code>",1,2,3,4".split(",");</code></p> <p>What would you expect? Right, an empty-string to start with. In your case you have a 'nothing' in front of the first 'a' as well as one behind it.</p> <p>Update: comments indicate this explanation is not enough of an explanation (which it may not be)... but, it really is this simple: the engine starts at the beginning of the string, and it looks to see if what's in front of it matches the pattern. If it does, it assigns what's behind it to a new item in the split.</p> <p>On the first character, it has "" (nothing behind it), and it looks to see if there's "" (the pattern) in front of it. There is, so it creates a "" match.</p> <p>It then moves on, and it has 'a' behind it, and again, it again has "" in front of it. So the second result is an "a" string.</p> <p>An interesting observation is that, if you use <code>split("", -1)</code> you will also get an empty-string result in the last position of the result array.</p> <hr> <p>Edit 2: If I wrack my brains further, and consider this to be an academic exercise (I would not recommend this in real life...) I can think of only one good way to do a regex <code>split()</code> of a String into a <code>String[]</code> array with 1 character in each string (as opposed to char[] - which other people have given great answers for....).</p> <pre><code>String[] chars = str.split("(?&lt;=.)", str.length()); </code></pre> <p>This will look behind each character, in a non-capturing group, and split on that, and then limit the array size to the number of characters (you can leave the <code>str.length()</code> out, but if you put <code>-1</code> you will get an extra space at the end)</p> <p>Borrowing nitro2k01's alternative (below in the comments) which references the string beginning and end, you can split reliably on:</p> <pre><code>String[] chars = str.split("(?!(^|$))"); </code></pre>
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    1. POjava - after splitting a string, what is the first element in the array?
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    1. COIt doesn't explain how "" works as a regular expression which is at issue here. I've done some regex stuff, and have never tried any kind of matching with "", such that I understand how it works exactly. Someone who has, or who knows the java regex code internally might be able to explain this better.
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    2. COThis seems to be a pretty clear explanation. "Split the string when you encounter nothing, then go to the next character". Note - that second part is important. You don't get an infinite array of empty strings; only the first element returned is nothing, after that the `split` algorithm increments by at least one. But not the first time. Still a bit odd...
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    3. COIf I want to stick with the split() function, is there any way that I can modify the code to circumvent the problem?
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