奇怪的 Groovy / Java 字符串比较行为

Question

Consider the following script:

def a = new HashSet()
def str1 = "str1"
def str2 = "str2"
def b = "$str1-$str2"
def c = "str1-str2"
println "b: $b"
println "c: $c"
println "b.equals(c): " + (b.equals(c))
println "b == c: " + (b == c)
println "b.compareTo(c): " + (b.compareTo(c))

a.add(b)
println "a.contains(c): " + a.contains(c)

Which has the following output when run with Groovy 1.8 and JDK 1.6.0_14:

b: str1-str2                                                                                                               
c: str1-str2
b.equals(c): false
b == c: true
b.compareTo(c): 0
a.contains(c): false

The two strings "b" and "c" print the same sequence of characters yet b.equals(c) is false. According to JDK 1.6 manual, the equals() function should return:

Compares this string to the specified object. The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.

Why does equals() not return the value as documented and demonstrated above? Strangely, compareTo() returns 0!

Answer 1

The problem is answered on the Groovy GString page . I need to call toString() on the GString.