equals小疑点。

public class StringComparison {    public static void main(String[] args) {        String s1 = "java isn't just for breakfast";        String s2 = "JAVA isn't just for breakfast";                if(s1.equals(s2));            System.out.println("The two lines are equal===");                System.out.println("The two lines are not equal----1");                if(s2.equals(s1))            System.out.println("the two lines are equal");                System.out.println("the two lines are not equal------2");                if(s1.equalsIgnoreCase(s2))            System.out.println("But the lines aer equal,ignorring case");        System.out.println("Lines are not equal,even ignoring case");                String s3 = "A cup is a joy forever";                if(s1.equalsIgnoreCase(s3))            System.out.println("two lines are equals");    }}