Classes

Constructors

• Can be overloaded.
• Formal parameters do not need types.
• Can be called either with positional or named parameters1

Default Constructors

if you do not create a constructor (i.e., you use the default constructor), you always can invoke the default constructor with named parameters, which map instance properties to actual parameters:

 ```groovy
 class PersonWOConstructor {                                  
     String name
     Integer age
 }
 
 // The default constructor for the class above can be invoked in any of the following ways:
 def person4 = new PersonWOConstructor()                      
 def person5 = new PersonWOConstructor(name: 'Marie')         
 def person6 = new PersonWOConstructor(age: 1)                
 def person7 = new PersonWOConstructor(name: 'Marie', age: 2)
 ```

 This saves you from having to overload the constructor many times to support the different parameter lists.

Declared Constructors

References

• http://groovy-lang.org/objectorientation.html
• http://groovy-lang.org/style-guide.html#_initializing_beans_with_named_parameters_and_the_default_constructor

Notes

1. http://groovy-lang.org/objectorientation.html#_constructors

   In Groovy there are two ways to invoke constructors: with positional parameters or named parameters. The former one is like we invoke Java constructors, while the second way allows one to specify the parameter names when invoking the constructor.