To find all places where a particular class, method or variable is used in the whole project by positioning the caret at the symbol's name or at its usage in code.

`Alt` + `F7`

All hotkeys for IntelliJ (Linux)

Productivity To quickly open any class.	`Ctrl` + `N`
Productivity To quickly open any file.	`Ctrl` + `Shift` + `N`
Productivity Toggle tools (maximize/minimize code window).	`Ctrl` + `Shift` + `F12`
Productivity Code completion.	`Ctrl` + `Space`
Productivity To find all places where a particular class, method or variable is used in the whole project by positioning the caret at the symbol's name or at its usage in code.	`Alt` + `F7`
Productivity To quickly see the documentation for the class or method used at the editor's caret.	`Crtl` + `P`
Editing Basic code completion (the name of any class, method or variable)	`Ctrl` + `Space`
Editing Smart code completion (filters the list of methods and variables by expected type)	`Ctrl` + `Shift` + `Space`
Editing Complete statement	`Ctrl` + `Shift` + `Enter`
Editing Parameter info (within method call arguments)	`Ctrl` + `P`
Editing Quick documentation lookup	`Ctrl` + `Q`
Editing External Doc	`Shift` + `F1`
Editing Brief Info	`Ctrl` + mouse over code
Editing Show descriptions of error or warning at caret	`Ctrl` + `F1`
Editing Generate code... (Getters, Setters, Constructors, hashCode/equals, toString)	`Alt` + `Insert`
Editing Override methods	`Ctrl` + `O`
Editing Implement methods	`Ctrl` + `I`
Editing Surround with… (if..else, try..catch, for, synchronized, etc.)	`Ctrl` + `Alt` + `T`
Editing Comment/uncomment with line comment	`Ctrl` + `/`
Editing Comment/uncomment with block comment	`Ctrl` + `Shift` + `/`
Editing Select successively increasing code blocks	`Ctrl` + `W`
Editing Decrease current selection to previous state	`Ctrl` + `Shift` + `W`
Editing Context info	`Alt` + `Q`
Editing Show intention actions and quick-fixes	`Alt` + `Enter`
Editing Reformat code	`Ctrl` + `Alt` + `L`
Editing Optimize imports	`Ctrl` + `Alt` + `O`
Editing Auto-indent line(s)	`Ctrl` + `Alt` + `I`
Editing Indent/unindent selected lines	`Tab` / `Shift` + `Tab`
Editing Cut current line or selected block to clipboard	`Ctrl` + `X` / `Shift` + `Delete`
Editing Copy current line or selected block to clipboard	`Ctrl` + `C` / `Ctrl` + `Insert`
Editing Paste from clipboard	`Ctrl` + `V` / `Shift` + `Insert`
Editing Paste from recent buffers...	`Ctrl` + `Shift` + `V`
Editing Duplicate current line or selected block	`Ctrl` + `D`
Editing Delete line at caret	`Ctrl` + `Y`
Editing Smart line join	`Ctrl` + `Shift` + `J`
Editing Smart line split	`Ctrl` + `Enter`
Editing Start new line	`Shift` + `Enter`
Editing Toggle case for word at caret or selected block	`Ctrl` + `Shift` + `U`
Editing Select till code block end/start	`Ctrl` + `Shift` + `]` / `[`
Editing Delete to word end	`Ctrl` + `Delete`
Editing Delete to word start	`Ctrl` + `Backspace`
Editing Expand/collapse code block	`Ctrl` + NumPad `+` / `-`
Editing Expand all / collapse all	`Ctrl` + `Shift` + NumPad `+` / `-`
Editing Close active editor tab	`Ctrl` + `F4`
Editing Find usages / Find usages in file	`Alt` + `F7` / `Ctrl` + `F7`
Editing Highlight usages in file	`Ctrl` + `Shift` + `F7`
Editing Show usages	`Ctrl` + `Alt` + `F7`
Editing Copy	`F5`
Editing Move	`F6`
Editing Safe Delete	`Alt` + `Delete`
Editing Rename	`Shift` + `F6`
Editing Change Signature	`Ctrl` + `F6`
Editing Inline	`Ctrl` + `Alt` + `N`
Editing Extract Method	`Ctrl` + `Alt` + `M`
Editing Extract Variable	`Ctrl` + `Alt` + `V`
Editing Extract Field	`Ctrl` + `Alt` + `F`
Editing Extract Constant	`Ctrl` + `Alt` + `C`
Editing Extract Parameter	`Ctrl` + `Alt` + `P`
Search/Replace Search everywhere	Double Shift
Search/Replace Find	`Ctrl` + `F`
Search/Replace Find next / Find previous	`F3` / `Shift` + `F3`
Search/Replace Replace	`Ctrl` + `R`
Search/Replace Find in path	`Ctrl` + `Shift` + `F`
Search/Replace Replace in path	`Ctrl` + `Shift` + `R`
Search/Replace Search structurally (Ultimate Edition only)	`Ctrl` + `Shift` + `S`
Search/Replace Replace structurally (Ultimate Edition only)	`Ctrl` + `Shift` + `M`
Compile and Run Make project (compile modifed and dependent)	`Ctrl` + `F9`
Compile and Run Compile selected file, package or module	`Ctrl` + `Shift` + `F9`
Compile and Run Select configuration and run	`Alt` + `Shift` + `F10`
Compile and Run Select configuration and debug	`Alt` + `Shift` + `F9`
Compile and Run Run	`Shift` + `F10`
Compile and Run Debug	`Shift` + `F9`
Compile and Run Run context configuration from editor	`Ctrl` + `Shift` + `F10`
Debugging Commit project to VCS	`Ctrl` + `K`
Debugging Update project from VCS	`Ctrl` + `T`
Debugging View recent changes	`Alt` + `Shift` + `C`
Debugging ‘VCS’ quick popup	`Alt` + `
Debugging Step over	`F8`
Debugging Step into	`F7`
Debugging Smart step into	`Shift` + `F7`
Debugging Step out	`Shift` + `F8`
Debugging Run to cursor	`Alt` + `F9`
Debugging Evaluate expression	`Alt` + `F8`
Debugging Resume program	`F9`
Debugging Toggle breakpoint	`Ctrl` + `F8`
Debugging View breakpoints	`Ctrl` + `Shift` + `F8`
Live Templates Surround with Live Template	`Ctrl` + `Alt` + `J`
Live Templates Insert Live Template	`Ctrl` + `J`
Live Templates Iteration according to Java SDK 1.5 style	`Ctrl` + `J` - iter
Live Templates Check object type with instanceof and downcast it	`Ctrl` + `J` - inst
Live Templates Iterate Collection / Iterate elements of java.util.Collection	`Ctrl` + `J` - itco
Live Templates Iterate Itterator / IIterate elements of java.util.Iterator	`Ctrl` + `J` - itit
Live Templates Iterate List / Iterate elements of java.util.List	`Ctrl` + `J` - itli
Live Templates Public static final	`Ctrl` + `J` - psf
Live Templates throw new	`Ctrl` + `J` - thr
Navigation Go to class	`Ctrl` + `N`
Navigation Go to file	`Ctrl` + `Shift` + `N`
Navigation Go to symbol	`Ctrl` + `Alt` + `Shift` + `N`
Navigation Go to next/previous editor tab	`Alt` + Right/Left
Navigation Go back to previous tool window	`F12`
Navigation Go to editor (from tool window)	`Esc`
Navigation Hide active or last active window	`Shift` + `Esc`
Navigation Close active run/messages/find/... tab	`Ctrl` + `Shift` + `F4`
Navigation Go to line	`Ctrl` + `G`
Navigation Recent files popup	`Ctrl` + `E`
Navigation Navigate backward / navigate forward	`Ctrl` + `Alt` + `Arrow left` / `Arrow right`
Navigation Navigate to last edit location	`Ctrl` + `Shift` + `Backspace`
Navigation Select current file or symbol in any view	`Alt` + `F1`
Navigation Go to declaration	`Ctrl` + `B` / `Ctrl` + Click
Navigation Go to implementation(s)	`Ctrl` + `Alt` + `B`
Navigation Open quick definition lookup	`Ctrl` + `Shift` + `I`
Navigation Go to type declaration	`Ctrl` + `Shift` + `B`
Navigation Go to super-method/super-class	`Ctrl` + `U`
Navigation Go to previous/next method	`Alt` + `Arrow up` / `Arrow down`
Navigation Move to code block end / move to code start	`Ctrl` + `]` / `[`
Navigation File structure popup	`Ctrl` + `F12`
Navigation Type hierarchy	`Ctrl` + `H`
Navigation Method hierarchy	`Ctrl` + `Shift` + `H`
Navigation Call hierarchy	`Ctrl` + `Alt` + `H`
Navigation Next/previous highlighted error	`F2` / `Shift` + `F2`
Navigation Edit source / View source	`F4` / `Ctrl` + `Enter`
Navigation Show navigation bar	`Alt` + `Home`
Navigation Toggle bookmark	`F11`
Navigation Toggle bookmark with mnemonic	`Ctrl` + `F11`
Navigation Go to numbered bookmark	`Ctrl` + `0` ... `9`
Navigation Show bookmarks	`Shift` + `F11`
General Open corresponding tool window	`Alt` + `0` ... `9`
General Save all	`Ctrl` + `S`
General Synchronize	`Ctrl` + `Alt` + `Y`
General Toggle maximizing editor	`Ctrl` + `Shift` + `F12`
General Add to Favorites	`Alt` + `Shift` + `F`
General Inspect current file with current profile	`Alt` + `Shift` + `I`
General Quick switch current scheme	`Ctrl` + `
General Open Settings dialog	`Ctrl` + `Alt` + `S`
General Open Project Structure dialog	`Ctrl` + `Alt` + `Shift` + `S`
General Find Action	`Ctrl` + `Shift` + `A`
General Switch between tabs and tool window	`Ctrl` + `Tab`