declare the variable MIN_local locally at the start of the function
(your if-clause in the function read if (a[i]< MIN) { - can you spot the error)
int getMIN() {
// declare the variable locally at the start of the function
int MIN_local=11000;
for (int i=0; i<a.length; i++) {
if (a[i] < MIN_local) {
MIN_local = a[i];
}//if
}//for
return MIN_local;
}//function