Given the following, class PassA { public static void main(String [] args) { PassA p = new PassA(); p.start(); } void start() { long [] a1 = {3,4,5}; long [] a2 = fix(a1); System.out.print(a1[0] + a1[1] + a1[2] + " "); System.out.println(a2[0] + a2[1] + a2[2]); } long [] fix(long [] a3) { a3[1] = 7; return a3; } }

the output is given as 15 15 ...so i think the compiler sees from left add the elements if present and if comes accross the string element then if there are any more elements after it then it concatnates with the first result ...

like when i run with ""+a1[0] + a1[1] + a1[2] i get 375

Start scanning from left. If you add String + long (Or int) the expression result will be String. If you are adding two long (or int), the result of expression will be long(or int). e.g. " "+ 3 + 7 + 5 = " 3" + 7 + 5 = " 37" + 5 = " 375" And 3 + 7 + " " + 5 = 10 5