java语言编程，求两个字符串的最大子串

package stringTest;

public class StringDemo4 {
	public static void main(String[] args) {
		String str1 = "Ilikejavaverymuch";
		String str2 = "java is useful";

		StringDemo4 sd4 = new StringDemo4();
		sd4.sop(sd4.getMaxSubString1(str1, str2));
	}

	/**
	 * 求两个字符串的最大相同子串,思路：
	 * 1、将短的字符串，按照长度递减的方式获取子串（核心）
	 * 2、将每个获取的子串，判断是否在长的字符串中存在
	 * */
	String getMaxSubString1(String str1, String str2) {
		String maxStr ="", minStr = "";
		maxStr = str1.length() > str2.length() ? str1:str2;
		minStr = (maxStr == str1) ? str2:str1;

		for(int i = 0; i < minStr.length(); i++){
			for(int start = 0, end = minStr.length()-i; end <= minStr.length(); start++, end++){
				if (maxStr.contains(minStr.substring(start, end))){
					return minStr.substring(start, end);
				}
			}
		}

		return "";
	}

	//打印字符串
	void sop(String str){
		System.out.println("str = " + str + "");
	}
}

打印结果：

str = java