【快捷鍵】
全局查找：Ctrl+Shift+R / Ctrl+Shift+F
格式化代碼：Ctrl+Alt+L
【Intellij Error】
Usage of API documented as @since 1.6+ This inspection finds all usages of methods that have @since tag in their documentation. This may be useful when development is performed under newer SDK version as the target platform for production：
Flie -> Project Structure -> Project Settings -> Modules -> "Your Module Name" -> Sources ->Language Level ，然後將其更改爲所需級別，即8或"項目默認語言級別"
【包名呈現層級顯示 】