Copy from IntelliJ help https://www.jetbrains.com/help/idea/2016.3/keyboard-shortcuts-you-cannot-miss.html
IntelliJ IDEA also provides the default keymap reference in the pdf format. To view the keymap reference, choose
IntelliJ IDEA, as a keyboard-centric IDE, suggests keyboard shortcuts for most of its actions. In this topic, you can find a short list of the most indispensable of them, to make your first steps with IntelliJ IDEA easy.
See the detailed list of default keyboard shortcuts in the Keyboard Shortcuts Reference and learn how to customize your preferred keymap in the Configuring Keyboard Shortcuts section.
| Action | Shortcut |
|---|---|
| Find action by name | Ctrl+Shift+A |
| Show the list of available intention actions . | Alt+Enter |
| Switch between views (Project,Structure, etc.). | Alt+F1 |
| Switch between the tool windows and files opened in the editor. | Ctrl+Tab |
| Show the Navigation bar. | Alt+Home |
| Insert a live template. | Ctrl+J |
| Surround with a live template. | Ctrl+Alt+J |
| Edit an item from the Project or another tree view. | F4 |
| Comment or uncomment a line or fragment of codewith the line or block comment. | Ctrl+Slash Ctrl+Shift+Slash |
| Find class or file by name. | Ctrl+N Ctrl+Shift+N |
| Duplicate the current line or selection. | Ctrl+D |
| Incremental expression selection. | Ctrl+W and Ctrl+Shift+W |
| Find/replace text string in the current file. | Ctrl+F Ctrl+R |
| Find/replace text in the project or in the specified directory | Ctrl+Shift+F Ctrl+Shift+R |
| Search everywhere. | Double-press Shift |
| Quick view the usages of the selected symbol. | Ctrl+Shift+F7 |
| Expand or collapse a code fragment in the editor. | Ctrl+NumPad Plus Ctrl+NumPad - |
| Invoke code completion. | Ctrl+Space |
| Smart statement completion. | Ctrl+Shift+Enter |
| Smart completion | Ctrl+Shift+Space |
| Show the list of available refactorings (Refactor This). | Ctrl+Shift+Alt+T |
| Open PopUp Class or Function Document Window | Ctrl+Q |
The complete keymap reference is available from the main menu ().