在Galaxy S5和Android 5.1.1上的do / while语句中出现奇怪的行为

Question

I face strange behavior of do/while statement on Galaxy S5 and Android 5.1.1. If you have any information, let me know.

int i = 0;
int j = 0;

do {
    Log.d(TAG, "[test do-while 1] i = " + i + ", j = " + j);
    i = 0;
    Log.d(TAG, "[test do-while 2] i = " + i + ", j = " + j);
    i++;
    Log.d(TAG, "[test do-while 3] i = " + i + ", j = " + j);
    i++;
    Log.d(TAG, "[test do-while 4] i = " + i + ", j = " + j);
    j++;
    Log.d(TAG, "[test do-while 5] i = " + i + ", j = " + j);
} while (j < 5);

If I will run the program on Galaxy S5 with Android 5.1.1, output log is as follows.

D/MainActivity( 9856): [test do-while 1] i = 2, j = 0
D/MainActivity( 9856): [test do-while 2] i = 2, j = 0
D/MainActivity( 9856): [test do-while 3] i = 2, j = 0
D/MainActivity( 9856): [test do-while 4] i = 2, j = 0
D/MainActivity( 9856): [test do-while 5] i = 2, j = 1
D/MainActivity( 9856): [test do-while 1] i = 2, j = 1
D/MainActivity( 9856): [test do-while 2] i = 2, j = 1
D/MainActivity( 9856): [test do-while 3] i = 2, j = 1
D/MainActivity( 9856): [test do-while 4] i = 2, j = 1
D/MainActivity( 9856): [test do-while 5] i = 2, j = 2
D/MainActivity( 9856): [test do-while 1] i = 2, j = 2
D/MainActivity( 9856): [test do-while 2] i = 2, j = 2
D/MainActivity( 9856): [test do-while 3] i = 2, j = 2
D/MainActivity( 9856): [test do-while 4] i = 2, j = 2
D/MainActivity( 9856): [test do-while 5] i = 2, j = 3
D/MainActivity( 9856): [test do-while 1] i = 2, j = 3
D/MainActivity( 9856): [test do-while 2] i = 2, j = 3
D/MainActivity( 9856): [test do-while 3] i = 2, j = 3
D/MainActivity( 9856): [test do-while 4] i = 2, j = 3
D/MainActivity( 9856): [test do-while 5] i = 2, j = 4
D/MainActivity( 9856): [test do-while 1] i = 2, j = 4
D/MainActivity( 9856): [test do-while 2] i = 2, j = 4
D/MainActivity( 9856): [test do-while 3] i = 2, j = 4
D/MainActivity( 9856): [test do-while 4] i = 2, j = 4
D/MainActivity( 9856): [test do-while 5] i = 2, j = 5

If I will run the same program on other device or other o/s version, output is as follows.

D/MainActivity( 9515): [test do-while 1] i = 0, j = 0
D/MainActivity( 9515): [test do-while 2] i = 0, j = 0
D/MainActivity( 9515): [test do-while 3] i = 1, j = 0
D/MainActivity( 9515): [test do-while 4] i = 2, j = 0
D/MainActivity( 9515): [test do-while 5] i = 2, j = 1
D/MainActivity( 9515): [test do-while 1] i = 2, j = 1
D/MainActivity( 9515): [test do-while 2] i = 0, j = 1
D/MainActivity( 9515): [test do-while 3] i = 1, j = 1
D/MainActivity( 9515): [test do-while 4] i = 2, j = 1
D/MainActivity( 9515): [test do-while 5] i = 2, j = 2
D/MainActivity( 9515): [test do-while 1] i = 2, j = 2
D/MainActivity( 9515): [test do-while 2] i = 0, j = 2
D/MainActivity( 9515): [test do-while 3] i = 1, j = 2
D/MainActivity( 9515): [test do-while 4] i = 2, j = 2
D/MainActivity( 9515): [test do-while 5] i = 2, j = 3
D/MainActivity( 9515): [test do-while 1] i = 2, j = 3
D/MainActivity( 9515): [test do-while 2] i = 0, j = 3
D/MainActivity( 9515): [test do-while 3] i = 1, j = 3
D/MainActivity( 9515): [test do-while 4] i = 2, j = 3
D/MainActivity( 9515): [test do-while 5] i = 2, j = 4
D/MainActivity( 9515): [test do-while 1] i = 2, j = 4
D/MainActivity( 9515): [test do-while 2] i = 0, j = 4
D/MainActivity( 9515): [test do-while 3] i = 1, j = 4
D/MainActivity( 9515): [test do-while 4] i = 2, j = 4
D/MainActivity( 9515): [test do-while 5] i = 2, j = 5

• If we convert the code to while or for statement, the issue does not occur.
• If we make a own log library with sync file i/o, the issue occur.
• Does not occur on Galaxy S4 and S6 or Android 5.0.2.

Answer 1

Probably not the answer you're looking for, but just as a test (because I'm curious): - declare i as final, and assign it a 0 value. - remove the increment statements for i.

If you're getting the same answer then: 1. You have i declared somewhere else as 2. 2. You've discovered a bug.

Also, does the issue occurs if you declare i as Integer instead of int? There's something to be learned here..