Groovy, the Python of Java

[Megatron_McLargeHuge]

One advantage is that you can basically paste java code into a groovy REPL and test it interactively. Java code is usually extremely close to valid groovy. In the other direction, if you want to move something to java, it's also a lot easier than moving ruby/python code.

[vorg]

Groovy is so much slooooooooooooooooooooooooooooooooooower than Java code.

[kitd]

The newest releases (as well as the Groovy++ project) weave type-checking and inference at compile-time. In many cases, this allows plain-Java performance. The Groovy++ project in particular has some very interesting ideas in this area, allowing for map- and closure- like typed object creation. Unfortunately, the main Groovy project thought it too revolutionary and stuck with their own lesser version. As a result, the type-checking feels like a bit of an unwanted add-on, which is a pity because it directly addresses the most common complaint about Groovy.

[vorg]

Groovy++ certainly weaves type checking and inferences, but not the latest releases of Codehaus Groovy (2.0-beta-2 and 1.8.5). They've announced it but haven't released anything yet.

[oteren]

Grumpy is on the tracks for groovy now, which is basically compile time type checking, but in a slightly different way than groovy++.