Java faster than C? [closed]

Answer 1

Your comparison of their runtime is unfair and flawed. You use default compiler options but Java and C differ on what optimizations they enable by default. And in general measuring performance without optimizations turned on is completely useless of itself, the output could completely change in the real world depending on which can be optimized more.

Java uses a JIT to optimize your code while it runs even with default options.

For gcc the default optimization option is -O0 which means there weren't any optimizations done at all. Try using -O2 or -O3 for a more fair comparison.

For example results on my machine are:

• C code with default compiler options = 12.5secs.
• C code with -O3 to enable optimization = 4.5secs.
• Java code = 8.5 secs.

Answer 2

first of all it is totally wrong to compare languages, sometimes you can compare compilers for the same language, but not languages itself

anyway, java could be faster just because it has JIT, which means during run-time java gathers some statistics and could perform additional optimizations or caching which are almost impossible with c compilers

though some c compilers have profiler-guided optimization loop and final result of such optimization will/could run faster neither java code

Answer 3

They are 2 different languages in design, and should be treated as such.

C is a low-level, executable-compiled language, that can do low-level hardware operations such as dynamic memory allocation, and accessing hardware drivers at a very low level. C is normally faster than Java, if it is written efficiently, but it always depends on the compiler. Some compilers support optimization on the compile time, to produce more efficient code, by removing redundant code and other unnecessary artefacts.

One reason that people say C is faster is because you can do allot more with it, such as use low-level multi threading, memory allocation (Via malloc), and other operations that could speed up the program's operation considerably.

Java, on the other hand, is compiled to JVM bytecode, which depends entirely on the JVM (Written in C++) for it's speed. Java has allot less low-level functionality than C, and therefore loses speed in some cases, where C would run allot faster.

Overall, the general reasons your program could lose performance in C is the fact that you

1. Used a bad compiler
2. Wrote inefficient code
3. Used slower functions, structures, etc.

But, in most cases, C normally runs considerably faster, and is known to have that over Java, which is one reason it lies at the core of most operating systems, and other advanced software.