Why JAVA foreach doesn't change element value? -

how come following prints boss , not bass?

string boss = "boss"; char[] array = boss.tochararray();  for(char c : array) {  if (c== 'o')      c = 'a';  } system.out.println(new string(array)); //how come not print out bass?it prints boss. 

you're changing iteration variable c. doesn't change contents of array. iteration variable copy of array element. if want modify array, need explicitly:

for (int = 0; < array.length; i++) {     if (array[i] == 'o') {         array[i] = 'a';     } } 

your original code equivalent (as per section 14.14.2 of jls) to:

for (int = 0; < array.length; i++) {     char c = array[i];     if (c == 'o') {         c = 'a';      } } 

changing value of local variable never change else - just changes local variable. assignment:

char c = array[i]; 

copies value in array local variable. doesn't associate local variable array element perpetually.