http://code.joejag.com/2009/new-language-features-in-java-7/

The new features are:

• Language support for collections (like Ruby . . . but apparently still no Hash literal — probably way too late to wedge that in)
• Automatic resource management (like Ruby’s IO objects that yield a reference to a block . . . but looks far less general)
• New type inference operator
• Underscores in numeric literals (1_000_000) (like Ruby)
• Strings in switch statements (like Ruby . . . but only for Strings, so no ‘case equals’ operator)
• binary literals (like Ruby)
• Simplified varargs

gem install cheat
# NOTE: If you're on Linux or OS/X and have a standard install (rather than using the ruby_switch.sh script, you want to do sudo gem install cheat)

If you run it under 1.9.x, you should get an error like so:

cheat regexp
/Users/jnorman/.gem/ruby/1.9.1/gems/cheat-1.2.1/lib/cheat.rb:150:in `cache_dir': uninitialized constant Cheat::PLATFORM (NameError)
	from /Users/jnorman/.gem/ruby/1.9.1/gems/cheat-1.2.1/lib/cheat.rb:16:in `sheets'
	from /Users/jnorman/.gem/ruby/1.9.1/gems/cheat-1.2.1/bin/cheat:4:in `<top (required)>'
	from /Users/jnorman/.gem/ruby/1.9.1/bin/cheat:19:in `load'
	from /Users/jnorman/.gem/ruby/1.9.1/bin/cheat:19:in `<main>'

What you want to do is edit the file producing the error (in my case, from the exception trace, /Users/jnorman/.gem/ruby/1.9.1/gems/cheat-1.2.1/lib/cheat.rb). Go to the line, and change the constant PLATFORM to RUBY_PLATFORM. Save the file.

And voila!

chelsea:~ jnorman$ cheat regexp
regexp:
  A regexp's form is written /pattern/modifiers where "pattern" is the regular
# much deleted

For help,

cheat cheat

You might be interested in this new post by Ola Bini who discusses the claim that if a project is very big, you need all of the helps from a statically-typed language (such as Java).

http://olabini.com/blog/2009/10/plan-to-write-big-software-and-you-have-already-lost/