June 2018 Update

Task/Special-variables/Java/special-variables.java

@@ -0,0 +1,30 @@
+import java.util.Arrays;
+
+public class SpecialVariables {
+
+    public static void main(String[] args) {
+
+        //String-Array args contains the command line parameters passed to the program
+        //Note that the "Arrays.toString()"-call is just used for pretty-printing
+        System.out.println(Arrays.toString(args));
+
+        //<Classname>.class might qualify as a special variable, since it always contains a Class<T>-object that
+        //is used in Reflection
+        System.out.println(SpecialVariables.class);
+
+
+        //The following are not really "variables", since they are properly encapsulated:
+
+        //System.getenv() returns a String-String-Map of environment-variables
+        System.out.println(System.getenv());
+
+        //System.getProperties() returns a Map of "things somebody might want to know", including OS and architecture
+        // the Java VM runs on, various paths like home direcoty of the user that runs the program, class (library) paths,
+        System.out.println(System.getProperties());
+
+        //Runtime.getRuntime() returns a Runtime-Object that contains "changing" data about the running Java VM's
+        // environment, like available processor cores or available RAM
+        System.out.println(Runtime.getRuntime().availableProcessors());
+
+    }
+}