用Java写出一段string和stringbuffer的代码

class Test6{
public static void main(String args[]){
String s1=”1234567″;
System.out.println( new StringBuffer(s1).reverse());
String s2=”MicrosoftSun”;
StringBuffer sw=new StringBuffer(s2.toLowerCase());
StringBuffer ss=new StringBuffer(sw.substring(4,10)).reverse();
System.out.println(ss);
String s3=”kico”;
StringBuffer st=new StringBuffer(s3);
st.insert(2,s3).insert(4,” &”);
System.out.println(st);
}
}