StringBuilder

Created: November-22, 2018

创建一个类型为 char 作为参数的新 StringBuilder 将导致使用参数 int capacity 调用构造函数，而不是使用参数 String string 调用：

 StringBuilder v = new StringBuilder('I'); //'I' is a character, "I" is a String.
 System.out.println(v.capacity()); --> output 73
 System.out.println(v.toString()); --> output nothing