java的exception解析

public void methodA(){
        
        //InputStream ioInputStream= new FileInputStream(file);
        methodB();//出错，需要throws或try/catch
    }
    public void methodB() throws IOException {
        int a=0;
        if(10/a==1){
            throw new ArithmeticException();//不出错
        }else{
            throw new IOException();//出错，需要throws或try/catch
        }
    }