For those new to both Java and Groovy

Java developers benefit from using Groovy, but so can those who don't already know Java:

1. Those who want to learn Java the easy way can learn Groovy first. They'll be productive sooner, and can go on to learn more about Java at their own pace.
2. Those who don't want to learn Java, but do want to access the power of the Java virtual machine and standard libraries when programming, can use Groovy instead.

Topics

Numerical Processing:
         Groovy Integer Math - choose from many types of integers

         Groovy BigDecimal Math - for high-precision decimal math

         Groovy Floating Point Math - for high-speed decimal math

Collections:
         Lists and Sets - group various items into a collection

         Object Arrays - fixed-size arrays for faster collections

         Maps and Sorted Maps - assign collected values to access keys

Text Processing:
         Characters in Groovy - access the full power of Unicode

         Strings and StringBuffers in Groovy - for handling strings of characters (NEW ON 30 APRIL 2007)

         Pattern Matching in Groovy - COMING SOON

Input and Output:
         Files in Groovy - access the file system easily (NEW ON 2 MAY 2007)

         Streams, Readers, and Writers - access data as a flow of information (NEW ON 6 MAY 2007)

         Streams around Specific Resources - COMING SOON

         Networking in Groovy - COMING SOON

Control Structures:
         Blocks, Closures, and Functions - compose your program from a wide variety of building blocks

         Expandos, Classes, and Categories - encapsulate your program's complexity

Other topics coming:
         program control
         enums
         Queues/Deques
         arrays
         exceptions
         permissions
         annotations
         multi-threading
         tree processing, builders, XML
         static typing
         interfaces
         inheritance, method overriding, multi-methods, casting
         method-to-syntax mappings (switch, for, as, operator overloading)
         packages, evaluate, class loading
         internationalization

Miscellaneous:
        Using Interceptors with the ProxyMetaClass - intercept calls to methods

        Java Reflection in Groovy - examine and manipulate objects that aren't known at compile time

Tutorial Aims:

1. Correctness: All code examples have been tested using Groovy 1.0 inside a script.
2. Completeness: The tutorials are detailed demonstrations of the classes, having plenty of code examples.

Only after creating all the detailed examples needed to introduce Groovy's syntax and core classes to Java newbies, will we then expand the explanations, re-sequence the information, add a "Getting Started" section, etc. Until then, it's correct and detailed, though a little raw.