what is faster - for or foreach?

i want to check all elements inside an array if (whatever(arrayelement))
i know foreach creates an iterator, but how does it work for an array? if performance is very important, should i use the old style for loop?


The performance of foreach for arrays is kind of optimal if jit is not dumb enough which is probably true. Let's consider the example java code:
void foo(Integer[] is) {
  for (Integer i : is) { 

The output of javap is:
void foo(java.lang.Integer[]);
   0:    aload_1 // load parameter on stack
   1:    astore_2 // store as a local variable, will be coalesced with the previous instruction into single register load when jit-compiled
   2:    aload_2 // load the local variable from stack, will be no-op
   3:    arraylength // assuming the variable on top of  the stack is of the array type, get its length
   4:    istore_3 // store array length into local
   5:    iconst_0 // push constant 0 onto stack
   6:    istore    4 // store into local
   8:    iload    4 // load local, will be no-op since it is already in the register
   10:    iload_3 // load array length, should be no-op, since it is already in the register
   11:    if_icmpge    34 //compare and branch to return when reached the end of the array
   14:    aload_2 // load the address of the array
   15:    iload    4 // load index
   17:    aaload // load the element of the array with given index.
   34:    return