Guice has a concept called develpment stages which affect how the library works. Guice is written with server-side applications in mind (it is from Google, after all) so the behaviour for production mode is to do a bunch of work up front so that it can catch errors as soon as possible.

The development mode defers work (i.e. object creation) until the last moment; Here’s how the Javadoc notes describe them:

• Development we want fast startup times at the expense of runtime performance and some up front error checking.

• Production we want to catch errors as early as possible and take performance hits up front.

• Tool we’re running in a tool (an IDE plugin for example).

Ignoring tool mode, this is exactly the opposite of the behaviour that you want to see for client-side development. For client applications you want to have an much error checking as possible during development but for production use (i.e. use by a real user) you want to go for faster start-up times.

Note that for production use it is also advantageous to defer error checking until later as well; after all, there is no point in refusing to start an app because feature ‘foo’ isn’t working, if the user doesn’t use or care about ‘foo’!