Re: Does Java has compiler options?
Sanny wrote On 10/05/07 14:00,:
In C language we can put -o etc to compile a program.
I want to compile java such that it do not do error checking at run
time to increase the efficiency of the code.
As when a/b is done it see diviision by 0 or not.
On many (perhaps most) implementations, this check
is performed by the CPU hardware/firmware as a by-product
of the division opcode. You can turn off the check by
replacing the CPU with a new model of your own design.
When assigning array1[55]="dfgdfg"; It checks whether array1[] size is
ok.
The JVM guarantees (or tries to guarantee) a safe
operating environment for all the code it runs, including
itself. In order to make the guarantee, it must defend
against this sort of error. Remember, if *you* can turn
off bounds checking, so can a less responsible programmer
whose code is loaded before yours ...
int ii="sdfsdf"; Here it checks for Casting etc.
The example won't compile, of course. But you'll
still get run-time checking to catch errors like
Object o = "42.0";
Double d = (Double) o;
Again, the JVM *must* make such checks if it is to be
able to extend its safety guarantees to your code. If it
didn't, that other guy's code could ruin yours.
I want that when the program is running it do not waste time in
verifying various things. As my Program is already tested and there is
no error left.
Donald Knuth offers monetary rewards to people who find
errors in his code or in his books. Are you willing to do
the same? You can offer an extravagantly large sum, since
your code is bug-free and you will never need to pay.
Can I ask the compiler to compile in such a way that it do not look
for errors when runniung and it helps speed up of my Program.
No. Some checks (array bounds, for example) are made
internally by the JVM and not by compiler-generated code.
Some (like casts) are initiated by compiler-generated code
and you could omit them by generating your own bytecodes.
You'd have trouble getting the JVM to load the resulting
classes, though: the bytecode verifier wouldn't like them.
And if it is possible how much fast the program will become when it do
not check for errors at runtime.
How fast does the wind blow in a vacuum?
I know It is possible in C++ Language but what about Java.
A lot of things are possible in C++ but not in Java.
You can read about some of them in the CERT advisories.
--
Eric.Sosman@sun.com