Idea practical shortcut key novice must see

debug In the process , Hold down alt Left click a variable to quickly check the current value of the variable

ctrl+h You can see all subclasses of the current class , It is helpful for code reading

Right click find usages You can see all the places where it is used

The small arrow on the left side of the interface can see all subclasses and implementation classes . Implementation classes are generally implemented in impl ending , This is a feature .