No enclosing instance of type X is accessible. Must qualify the allocation with an enclosing

今天准备写一个串口通信的Java类，其中有个内部类，用来执行读写操作，但是在main方法中声明内部类的时候有错误提示：

No enclosing instance of type SPComm is accessible. Must qualify the allocation with an enclosing instance of type SPComm(e.g. x.new A() where x is an instance of SPComm) 

public static void main(String[] args){init();CommThread commThread = new CommThread();//错误提示}

问题就出在CommThread这个内部类，它不是static的：

private class CommThread extends Thread{private final InputStream commInputStream;private final OutputStream commOutputStream;public CommThread(){commInputStream = inputStream;commOutputStream = outputStream;}

父类的static方法不能调用非static的成员，所以修改的方法是把CommThread类修改为static的：

private static class CommThread extends Thread...