Groovy Day 2 : Differences in term of readability between Java and Groovy

For this article, we will see the differences of readability between an "old" language (Java) and a dynamic language (Groovy). You will see at first the evolution of Java to try to become more readable for the novice (and less tiring for the advance developper). The second part is the Groovy version of the same code and you will see the difference very easily.
I decided to use a simple example of a creation of HashMap and store in it the names of the seasons and the related adjectives.

First code snippet is a Java 1.4 code.

class HashMapJavaShow {
   public static void main(String[] args) {
      // creation of the hashmap
      HashMap<String, String> seasons = new HashMap<String, String>();
      
      // insertion of data, key => value
      // in this example we take the name of the season as key
      // and the related adjective as value
      seasons.put("spring", "vernal");
      seasons.put("summer", "estival");
      seasons.put("automn", "autumnal");
      seasons.put("winter", "hibernal");
      
      // before 1.5 we were forced to use an iterator
      Iterator iter = seasons.iterator();
      // loop until the iterator has not more element
      while(iter.hasNext()){
         // retrieve the current element and display it
         // using its default method toString()
         System.out.println(iter.next());
      }
   }
}

Groovy Day 1 : Truth (2/2)

The second part of the post on Groovy Truth is about collections and custom conversion to boolean. First the collections, in Groovy, a collection can be tested for nullity and emptiness at the same time.

List list1 = [2,3,5] // way that groovy declare List, in this case, an ArrayList is used
List list2 = [] // empty list
List list3 = null

assert list1 // test is the object is null, if it's not the case, test emptiness on collections
assert !list2 // the list is non-null but empty
assert !list3 // the list is null

Groovy Day 1 : Truth (1/2)

This post is the first of the serie on Groovy discovery. To start easily the learning of Groovy, we need to understand the differences with Java. Groovy is a language that is compiled in bytecode like Java. The bytecode is then read by the same JVM. In other words, Groovy can use Java library (all the .jar that you can find in the internet, quite amazing) and Java can use Groovy library too ! The magic of bytecode in some sense. We could also imagine an interaction with Scala or JRuby etc. all the JVM language are intercompatible. This was for introduction, let's discover the first real part. The Groovy Truth is something very weird for an old Java developper. In Java we have some really particular cases to learn and understand to avoid common mistakes.