小编Dan*_*ang的帖子

什么Disconnected from the target VM, address: '127.0.0.1:51928', transport: 'socket'意思？

这是我的代码：

import java.math.BigDecimal;
public class puzzle2 {
    public static void main(String args[]){
        System.out.println(2.00-1.10);  //0.8999999999999999
        System.out.println(new BigDecimal("2.00").subtract(new BigDecimal("1.10")));    //0.10
    }
}

结果是

Connected to the target VM, address: '127.0.0.1:51928', transport: 'socket'

0.8999999999999999

0.90

Disconnected from the target VM, address: '127.0.0.1:51928', transport: 'socket'

我有一个问题java.lang.String.split()。

String str = "aaaaa";
String[] str1 = str.split("a");
str = "aaaaa ";
String[] str2 = str.split("a");

System.out.println(Arrays.toString(str1));
System.out.println(Arrays.toString(str2));

结果是

str1 == null
str2 == ["", "", "", "", "", " "]

为什么会str1这样呢？