"def" keyword in groovy

def actually defines the scope of the variable being defined


x = 4
public function() {
println x;
}
function()


o/p -> 4

whereas 

def x = 4
public function() {
println x;
}
function()

o/p -> 

groovy.lang.MissingPropertyException: No such property: x for class: Script1
 at Script1.function(Script1.groovy:3)
 at Script1.run(Script1.groovy:5)

so the the declaration without def makes it global .

But people say that it is good to use variable declarations with def 

so that , it does not unnecessarily interfere with the variables 

inside functions 

I got a rough idea from

http://stackoverflow.com/questions/184002/groovy-whats-the-purpose-of-def-in-def-x-0