Set and Retrieve system (JVM) and environment (OS) variables in java and groovy

JVMSystemProperties.java

// Java System properties
// =======================
// http://docs.oracle.com/javase/tutorial/essential/environment/properties.html
// http://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html
/*
Key     Meaning
================
"file.separator" 	Character that separates components of a file path. This is "/" on UNIX and "\" on Windows.
"java.class.path" 	Path used to find directories and JAR archives containing class files. Elements of the class path are separated by a platform-specific character specified in the path.separator property.
"java.home" 	Installation directory for Java Runtime Environment (JRE)
"java.vendor" 	JRE vendor name
"java.vendor.url" 	JRE vendor URL
"java.version" 	JRE version number
"line.separator" 	Sequence used by operating system to separate lines in text files
"os.arch" 	Operating system architecture
"os.name" 	Operating system name
"os.version" 	Operating system version
"path.separator" 	Path separator character used in java.class.path
"user.dir" 	User working directory // where the user os the OS was when launching this jvm, not where the java file executed was.
"user.home" 	User home directory // In Windows: e.g. Users/rmoreno
"user.name" 	User account name

// http://stackoverflow.com/questions/8098564/is-it-possible-to-specify-java-system-properties-when-running-groovy-from-comman
/*
System properties are set on the java and groovy command line (CLI) using the 
  java -Dpropertyname=value appName
syntax. 

They can also be added at runtime using 
  System.setProperty(name, value) 
or via the various 
  System.getProperties().load() 
methods.

  System.getProperties() 
lists all java system properties, and those set from command line will be there, 
but there's no way to distinguish those from the other properties added by the system.

Note that you can also set system properties with the environment variable JAVA_TOOL_OPTIONS
*/

// Directory of execution (not whee the java file is):
String workingDir = System.getProperty("user.dir");  
// or 
String currentDir = new File(".").getAbsolutePath();