Why add Groovy to Java? - Making Java Groovy - page 13

@EqualsAndHashCode
class Task {
String name
int priority
Date startDate
Date endDate
String toString() { "($name,$priority,$startDate,$endDate)" }
}
Seriously, that's the whole class, and it does include overrides of the equals and
hashCode methods. Groovy classes are public by default, as are Groovy methods. At-
tributes are private by default. Access to an attribute is done through dynamically gener-
ated getter and setter methods, so even though it looks like we're dealing with individual
fields we're actually going through getter and setter methods. Also, Groovy automatically
provides a map-based constructor that eliminates the need for lots of overloaded construct-
ors. The @EqualsAndHashCode annotation represents an Abstract Syntax Tree (AST)
transformation that generates the associated methods. Finally, I use a Groovy string with its
parameter substitution capabilities to convert a task into a string.
Groovy Feature
Groovy's dynamic generation capabilities drastically reduce the amount of code required
in a class, letting you focus on the essence rather than the ceremony.
Java also includes checked exceptions, which are a mixed blessing at best. The philosophy
is to catch (no pun intended) problems early in the development cycle, which is also sup-
posed to be an advantage to static typing.
1.1.4. Groovy makes testing Java much easier
Just because a class compiles doesn't mean it's implemented correctly. Just because you've
prepared for various exceptions doesn't mean the code works properly. You've still got to
test it, or you don't really know. [ 5 ]
5 My favorite example of this comes from a friend who used to teach C++ back when that language was shiny and
new. He looked at a student's code, and it was a mess. Then he noticed the first line was /* and the last line was */ .
He said, “You commented out your entire program.” The student shrugged and said, “That's the only way I could
get it to compile!”