Groovy: Optional typing

Groovy is dynamically typed language, you no need to specify the type of a variable, Groovy deduce the type from the value that a variable hold.

HelloWorld.groovy

a = 10
b = 20
c = 30
d = 40l

e = 20.05f
f = 20.05

g = 'c'
h = true

println "a : ${a}, class : ${a.class}"
println "b : ${b}, class : ${b.class}"
println "c : ${c}, class : ${c.class}"
println "d : ${d}, class : ${d.class}"
println "e : ${e}, class : ${e.class}"
println "f : ${f}, class : ${f.class}"
println "g : ${g}, class : ${g.class}"
println "h : ${h}, class : ${h.class}"

Output

a : 10, class : class java.lang.Integer
b : 20, class : class java.lang.Integer
c : 30, class : class java.lang.Integer
d : 40, class : class java.lang.Long
e : 20.05, class : class java.lang.Float
f : 20.05, class : class java.math.BigDecimal
g : c, class : class java.lang.String
h : true, class : class java.lang.Boolean

Because of this dynamic nature, you can assign any type of value to the variable.

HelloWorld.groovy

a = 10
println "a : ${a}, class : ${a.class}"

a = "Krishna"
println "a : ${a}, class : ${a.class}"

a = true
println "a : ${a}, class : ${a.class}"

Output

a : 10, class : class java.lang.Integer

a : Krishna, class : class java.lang.String

a : true, class : class java.lang.Boolean

As you see above example, I assigned 10 to the variable ‘a’, again I assigned a string to the variable ‘a’, and again I assigned a Boolean value to the variable ‘a’.

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