Java's time performance has been comparable to C++ for many years now, especially in the realm of file I/O where SCIFIO is focused. According to one thorough study performed in 2005, "Java often outperforms C++ in operations such as memory allocation and file I/O while C++ often outperforms Java in arithmetic and trigonometric operations." This statement is corroborated in an earlier study from 2004 that also includes an I/O benchmark: "If we exclude the trigonometry component, Java performed virtually identically to Visual C++, the fastest of Microsoft's languages." Some of the theoretical basis for such results is discussed in another 2004 article, which also finds that "Java performance on numerical code is comparable to that of C++, with hints that Java's relative performance is continuing to improve."

We have seen two refutations ([1][2]) of these figures, but neither includes an I/O benchmark, and according to their results Java's computational performance is within a factor of two of C++'s. Even from a pessimistic perspective, we believe the trade-off is acceptable when considering the other advantages of Java such as cross-platform deployment, widespread support and ease of development. As the second article above states: "It seems that it's much, much easier to create a well performing program in Java. So, please consider it for a moment before you start recoding your Java program in C++ just to make it faster."

For further reading, check out this June 2010 article on popular Java myths, and Wikipedia's comparison of Java performance to other languages.