15.9.2 Example: Evaluation Order

In an array creation expression (§15.9), there may be one or more dimension expressions, each within brackets. Each dimension expression is fully evaluated before any part of any dimension expression to its right.

Thus:

class Test {
	public static void main(String[] args) {
		int i = 4;
		int ia[][] = new int[i][i=3];
		System.out.println(
			"[" + ia.length + "," + ia[0].length + "]");
	}
}

prints:

[4,3]

because the first dimension is calculated as 4 before the second dimension expression sets i to 3.

If evaluation of a dimension expression completes abruptly, no part of any dimension expression to its right will appear to have been evaluated. Thus, the example:

class Test {

	public static void main(String[] args) {
		int[][] a = { { 00, 01 }, { 10, 11 } };
		int i = 99;
		try {
			a[val()][i = 1]++;
		} catch (Exception e) {
			System.out.println(e + ", i=" + i);
		}
	}

	static int val() throws Exception {
		throw new Exception("unimplemented");
	}

}

prints:

java.lang.Exception: unimplemented, i=99

because the embedded assignment that sets i to 1 is never executed.