Randomの種

2つのRandomインスタンスが同じシードを使用し、同じ順序でメソッドを呼び出すと、同じ数値シーケンスが生成されます.

public static void main(String[] args) {
		Random rand = new Random(50);
		System.out.println("nextBoolean():" + rand.nextBoolean());
		byte[] buffer = new byte[16];
		rand.nextBytes(buffer);
		System.out.println(Arrays.toString(buffer));
		System.out.println(rand.nextDouble());
		System.out.println(rand.nextFloat());
		System.out.println(rand.nextInt());
		System.out.println(rand.nextInt(26));
		Random rand2 = new Random(50);
		System.out.println("nextBoolean():" + rand2.nextBoolean());
		byte[] buffer2 = new byte[16];
		rand2.nextBytes(buffer2);
		System.out.println(Arrays.toString(buffer2));
		System.out.println(rand2.nextDouble());
		System.out.println(rand2.nextFloat());
		System.out.println(rand2.nextInt());
		System.out.println(rand2.nextInt(26));

	}

結果:

nextBoolean():true
[-8, 115, 15, -103, -29, 116, 57, -99, 81, -20, 88, -46, 78, -12, 31, -97]
0.48963797841008827
0.7030554
-942771064
24
nextBoolean():true
[-8, 115, 15, -103, -29, 116, 57, -99, 81, -20, 88, -46, 78, -12, 31, -97]
0.48963797841008827
0.7030554
-942771064
24