hello  yq1012

public static void main(String[] args) {
StringBuilder s1 = new StringBuilder("hello");
StringBuilder s2 = new StringBuilder("yq1012");
show(s1, s2);
System.out.println(s1 + "......." + s2);
}

private static void show(StringBuilder s1, StringBuilder s2) {

s1.append(s2);

s1 = s2;
}