It is very unfortunate that some people are still not aware of the fact that Java performance is comparable to that of C++. This blog piece collects the evidence to support this claim.
The wrong perception about Java slowness is by-and-large because Java 1 in 1995 was indeed slower than C++. Java has improved a lot since then, e.g., hotspot. It is now version 6 and soon will be version 7. Java is now a competitive technology comparing to C/C++. In fact, in order to realistically optimize for C/C++, you need to find the “right” programmer to code it. This programmer needs to be aware of all the performance issues of C/C++, profiling, code optimization such as loop unfolding, and may even need to write code snippets in assembly. An average Joe coding in C/C++ is probably not any faster than coding in Java.
(I am in general against code optimization techniques because they make the code unreadable to humans, hence unmaintainable, such as a lot of the FORTRAN/C/C++ code found in Netlib and Statlib.)
More importantly, most modern software runs on multiple cores. Code optimization techniques are dwarfed by parallel computing technologies. It is significantly easier and more efficient (and more enjoyable) to write concurrent programming code in Java than in C++. Therefore, to code high performance software, I personally prefer to code for multi-core, multi-CPU, and cloud in java rather than doing code optimization in C/C++.
(I AM NOT SURE WHY FORTRAN SURVIVES IN 2011. HOW ARE YOU SUPPOSED TO READ THOUSDANDS LINES OF CODE ALL IN UPPER/LOWER CASES WITH A BUNCH OF C’S AND GOTO’S EVERYWHERE?)
Briefly, my conclusion is that, among the general purpose programming languages (hence excluding Scala and etc.), we should use Java instead of C/C++, FORTRAN, Assembly and etc. whenever possible because Java is the easiest programming language to learn and work with without a sacrifice in performance.
(For me, Java is an easier language than C# because the Java IDE technology is far much better than the C# counterparts.)
The evidence I collect are listed below. Please feel free to expand the list.
- Java has recently won some major benchmark competitions.
- Recent independent studies seem to show that Java performance for high performance computing (HPC) is similar to FORTRAN on computation intensive benchmarks.