Getting Started with Groovy

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Groovy is a dynamically compiled object oriented language for the Java Virtual Machine (JVM).

Groovy features differentiating the language from Java 6 and earlier include:

• static and dynamic typing (with the def keyword), 
• closures
• operator overloading
• lists and associative arrays (maps) native syntax
• regular expression native support
• polymorphic iteration
• string embedded expressions
• additional helper methods
• safe navigation operator "?." to automatically check for nulls (for example, "variable?.method()", or "variable?.field").

Groovy as a dynamic language
A Groovy script is fully parsed, compiled, and generated before execution.  The process occurs under the hood, and the compiled version is not saved as an artifact of the process.


Maps

A map is used to store "associative arrays" or "dictionaries", an unordered collection of heterogeneous, named data.

For example, we want to store names and IQ scores:

scores = [ "Brett":100, "Pete":"Did not finish", "Andrew":86.87934 ]

Note that each of the values stored in the map is of a different type. Brett's is an integer, Pete's is a string, and Andrew's is a floating point number. We can access the values in a map in two main ways:

println scores["Pete"]
println scores.Pete