Modifier Modifier Plugin

Modifier Modifier Plugin for IntelliJ IDEA is a plugin which provides hotkey bindings for inserting and removing Java modifiers like synchronized, final, and public/protected/default/private.

Default Keys

Alt+Shift+A
Toggle abstract for current method or class
Alt+Shift+P
Cycle between private/package-private/protected/public for current field, method, constructor, or class (only package-private and public are cycled for non-inner classes)
Alt+Shift+F
Toggle final for current parameter, variable, field, method, or class
Alt+Shift+T
Toggle static for current field, method, or inner class
Alt+Shift+C
Toggle strictfp for current method or class
Alt+Shift+S
Toggle synchronized for current method
Alt+Shift+R
Toggle transient for current field
Alt+Shift+V
Toggle volatile for current field
Alt+Shift+O
Re-order modifiers for the current parameter, variable, field, method, or class according to your modifier order settings (configured in IDEA Settings)

You can download and install the plugin through the IDEA Plugins Settings.

You can download the source code.