Did you think that we were out of puzzlers?! Well, we might be - but the Groovy community sure isn’t! Per usual, we’ve got a bunch of awesomely puzzling contributions and you are going to have a shot at winning one of the prizes. Attend this session to have some fun while getting a workout in for those muscles - you’ll tease your brain and then stretch out for the flying t-shirts too!

3. ❤

4. ❤
❤
❤
❤
❤

7. Special Danveloper Amendment
1. When Dan get the question right:
a.Dan ________
b.Baruch ________
c.The audience ________
2. When Dan get the question wrong:
a.Dan ________
b.Baruch ________
c.The audience ________

12. def comments = ['FRIST!', 'YAS!']
println comments[3]

14. def comments = ['FRIST!', 'YAS!']
println comments[3]

15. def comments = ['FRIST!', 'YAS!']
println comments[3]
Calls default
methods
i is smaller than
size

18. def l1 = [1,2,3]
def l2 = []
def l3 = null
println "${l1?.first()}; ${l2?.first()}; ${l3?.first()}"

20. def l1 = [1,2,3]
def l2 = []
def l3 = null
println "${l1?.first()}; ${l2?.first()}; ${l3?.first()}"

21. def l1 = [1,2,3]
def l2 = []
def l3 = null
println "${l1?.first()}; ${l2?.first()}; ${l3?.first()}"
Calls different
default method!
Is empty!

22. println l2?.getAt(0)

25. String burger = 'burgers'
Long bites = 1
def m = [(burger): [bites]] as Map<String,List<Long>>
println m

27. String burger = 'burgers'
Long bites = 1
def m = [(burger): [bites]] as Map<String,List<Long>>
println m

28. def m = [(burger): [bites]] as Map<String,List<Long>>
println m
Evaluated as a bit
shift operation

29. def m = [(burger): [bites]] as Map<String,List<Long> >
def m = [(burger): [bites]] as Map<String,List<Long>>;

32. int burger = 0
int fries = ++burger++
println "Burger: $burger; Fries: $fries"

34. int burger = 0
int fries = ++burger++
println "Burger: $burger; Fries: $fries"

35. Calls increment
with value
int burger = 0
int fries = ++burger++
Calls increment
with same value

38. def thing1 = 0 % 20
def thing2 = 0 % (20 / 1)
println thing1 == thing2

40. def thing1 = 0 % 20
def thing2 = 0 % (20 / 1)
println thing1 == thing2

41. Right side is a
BigDecimal
def thing1 = 0 % 20
def thing2 = 0 % (20 / 1)
println thing1 == thing2
Both sides are
integers

42. def thing2 = 0 % (20 / 1).intValue()
def thing2 = 0.toBigDecimal().remainder((20 / 1)).intValue()

45. def static theAnswerToLifeTheUniverseAndEverything() {
{ 42 }
}
println theAnswerToLifeTheUniverseAndEverything()

47. def static theAnswerToLifeTheUniverseAndEverything() {
{ 42 }
}
println theAnswerToLifeTheUniverseAndEverything()

48. def static theAnswerToLifeTheUniverseAndEverything() {
{ 42 }
}
println theAnswerToLifeTheUniverseAndEverything()
Ambiguous return
statement

49. def static theAnswerToLifeTheUniverseAndEverything() {
return { 42 }
}
def static theAnswerToLifeTheUniverseAndEverything() {
return { -> 42 }
}

52. def pathPattern = $/.*/path/to/resource.*/$
Escape rules are
different for /
def multilinePattern = $/
We can even
have multilines.
/$

53. println $/.*The Doctor.*/$

55. println $/.*The Doctor.*/$

56. Confuses the
parser
println $/.*The Doctor.*/$

57. println ($/.*The Doctor.*/$)
I HAVE
RETURNED!

60. doubleVision = { x ->
println x
}
doubleVision("doubleVision${doubleVision}")

62. doubleVision = { x ->
println x
}
doubleVision("doubleVision${doubleVision}")

63. doubleVision = { x ->
println x
}
doubleVision("doubleVision${doubleVision}")

66. def static hello(n) {
['9': "GR8Conf 2${n}17"]
}
def result = hello 09
println result

68. def static hello(n) {
['9': "GR8Conf 2${n}17"]
}
def result = hello 09
println result

69. def static hello(n) {
['9': "GR8Conf 2${n}17"]
}
def result = hello 09
println result
Is it actually an
octal?

72. def tardis = new Tardis() {
static class Tardis {
def travel() { "It's Minneapolis in the year 1799!" }
}
}
println tardis.travel()

74. def tardis = new Tardis() {
static class Tardis {
def travel() { "It's Minneapolis in the year 1799!" }
}
}
println tardis.travel()

75. Maybe the order of initialization?

78. 1. Write readable code
2. Comment your tricks
3. Sometimes it’s only a bug
4. Use static analysis
(IntellijIDEA FTW!)
5. RTfM
6.The Parrot will fix it.

79. This is the 4th consecutive edition!
(Next time in uniform)
Puzzlers? Gotchas? Fetal-position
inducing behavior?
Write to us at:
• puzzlers@jfrog.com
• @Groovypuzzlers

81. Positive feedback?
• #groovypuzzlers
• @groovypuzzlers
• @jbaruch
• @danveloper
Negative feedback?
/dev/null