Performance Apache Common StringUtils Split and Google Guava Splitter

Last Friday I have a discussion with a colleague at SEITENBAU about the semantic of the split method of the Apache common lang StringUtils class. At the end we have compared the Google Guava Splitter API with the Apache commons Lang StringUtils split methods. Our opinion after that is that the source code based on Guava could be better understood and is much clearer.

After comparing the APIs, we have thought about which of the two APIs has the faster split implementation. So I have build simple performance test for the two String split implementations. The result has surprised me. The StringUtils split method is in my test case much faster then the Guava Splitter split method.

Test setup is I generate 5000 random strings with a length of 10000. The test strings contains commas to split the strings in the test. I invoke the Apache common spilt method and the Guava Splitter with the same test data, the performance result is shown in the table bellow.

Test Runs	1	2	3	4
Apache Common StringUtils.split(…)	126 ms	122 ms	121 ms	122 ms
Google Guava splitter.split(…)	352 ms	350 ms	346 ms	349 ms

Here the source of my simple performance test:
Why
Has anybody an idea why the Guava API in my test is slower then the StringUtils split method? I read that the Guava Splitter performance should be very good. Therefore, I am surprised about the result.

Here the dependencies I have used for the performance test: