private static int getMaxSame(String first0,String second0) {
		
		String first = first0.toLowerCase();
		String second = second0.toLowerCase();
		
		int fLen = first.length();
		int sLen = second.length();
		int d = (fLen <= sLen) ? fLen : sLen;
		String min = null;
		String max = null;
		String target = null;
		if (fLen <= sLen) {
			min = first;
			max = second;
		} else {
			min = second;
			max = first;
		}
		for (int i = d; i >= 1; i--) {
			for (int j = 0; j <= min.length() - i; j++) {
				target = min.substring(j, j + i);
				for (int k = 0; k <= max.length() - i; k++) {
					if (max.substring(k,k + i).equals(target)) {
						return i;
					}
				}
			}
		}
		return 0;
	}
 

下面是測試程式碼，一定要這樣輸入，兩個字串用空格隔開，然後用split方法讀取待處理的兩個字串：

public static void main(String[] args) {
Scanner sca = new Scanner(System.in);
		String strFirst = sca.nextLine();
		String[] strArray = strFirst.split(" ");
		System.out.println(getMaxSame(strArray[0], strArray[1]));
}