for(String str:res)

This is a for-each loop in Java used to iterate through a collection of elements. In this case, the collection is an array or list of Strings named "res".

The loop iterates through each element of the collection, assigning it to the variable "str" for each iteration.

Here's an example code snippet to illustrate how it works:

String[] res = {"apple", "banana", "cherry"};

for(String str:res){
  System.out.println(str);
}

// Output:
// apple
// banana
// cherry

In this example, the for-each loop will iterate through each element in the "res" array and print it to the console. The variable "str" is assigned to each element in turn, so "apple" is printed first, then "banana", and finally "cherry".