public class StringMethod {
    public static void main(String [] args) {
        String s1 = "hello world";
        StringBuffer s2 = new StringBuffer("hello world");
        System.out.println(s1.equals(s2));
    }// [color=#FF0000]为什么返回 false???    [/color]
}

public boolean equals(Object anObject) {
    if (this == anObject) {//直接比较引用是否相同，相同返回true
        return true;
    }
    if (anObject instanceof String) {//看传入类型是否是String，是的话比较String的内容，就是先看两个String类型的长度是否相同，不同跳出返回false,相同再比较组成String的char[]每个是否相同一样返回true
        String anotherString = (String)anObject;
        int n = count;
        if (n == anotherString.count) {
        char v1[] = value;
        char v2[] = anotherString.value;
        int i = offset;
        int j = anotherString.offset;
        while (n-- != 0) {
            if (v1[i++] != v2[j++])
            return false;
        }
        return true;
        }
    }
    return false;
    }