Loops in Apex class

For now(2016/9/26), Apex supports do-while, while, and for loops.

do-while:

Integer count = 1;
do {
    System.debug('count' + count);
    count++;
} while (count < 3);

while:

Integer count = 1;
while (count < 4) {
    System.debug('count' + count);
    count++;
}

for(loop in array):

Integer[] is = new Integer[]{1,2,3,4,5};
for (Integer i: is) {
 System.debug(i);
}

Queries can also be embedded in the special for syntax.

for (Test__c tmp : [SELECT Id FROM Test__c]) {
   // ...
}