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    <p>Here's an example that reads a list of CSV strings into a list of lists and then loops through that list of lists and prints the CSV strings back out to the console.</p> <pre><code>import java.util.ArrayList; import java.util.List; public class ListExample { public static void main(final String[] args) { //sample CSV strings...pretend they came from a file String[] csvStrings = new String[] { "abc,def,ghi,jkl,mno", "pqr,stu,vwx,yz", "123,345,678,90" }; List&lt;List&lt;String&gt;&gt; csvList = new ArrayList&lt;List&lt;String&gt;&gt;(); //pretend you're looping through lines in a file here for(String line : csvStrings) { String[] linePieces = line.split(","); List&lt;String&gt; csvPieces = new ArrayList&lt;String&gt;(linePieces.length); for(String piece : linePieces) { csvPieces.add(piece); } csvList.add(csvPieces); } //write the CSV back out to the console for(List&lt;String&gt; csv : csvList) { //dumb logic to place the commas correctly if(!csv.isEmpty()) { System.out.print(csv.get(0)); for(int i=1; i &lt; csv.size(); i++) { System.out.print("," + csv.get(i)); } } System.out.print("\n"); } } } </code></pre> <p>Pretty straightforward I think. Just a couple points to notice:</p> <ol> <li><p>I recommend using "List" instead of "ArrayList" on the left side when creating list objects. It's better to pass around the interface "List" because then if later you need to change to using something like Vector (e.g. you now need synchronized lists), you only need to change the line with the "new" statement. No matter what implementation of list you use, e.g. Vector or ArrayList, you still always just pass around <code>List&lt;String&gt;</code>.</p></li> <li><p>In the ArrayList constructor, you can leave the list empty and it will default to a certain size and then grow dynamically as needed. But if you know how big your list might be, you can sometimes save some performance. For instance, if you knew there were always going to be 500 lines in your file, then you could do: </p></li> </ol> <p><code>List&lt;List&lt;String&gt;&gt; csvList = new ArrayList&lt;List&lt;String&gt;&gt;(500);</code></p> <p>That way you would never waste processing time waiting for your list to grow dynamically grow. This is why I pass "linePieces.length" to the constructor. Not usually a big deal, but helpful sometimes.</p> <p>Hope that helps!</p>
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    1. COYour example, while rather detailed, is also rather misleading. Reading CSV file line by line and splitting lines at comma with no regard for surrounding quotes is asking for trouble.
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    2. COI agree with you and everyone else about CSV not being as simple as just splitting on commas. I got the impression that the crux of the question was demonstrating how to use generics & lists of lists, not parse CSV. I like OpenCSV as a package, so I definitely agree with you and everyone else and recommend something like that for the actual parsing of lines. Thanks for the feedback!
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