In Grails and Groovy, do Strings (in single quotes) outperform GStrings?

Question

Since in Grails and Groovy, single-quoted Strings are different class from GStrings (double quoted Strings allowing ${variable} value injection), is it more efficient to use single quotes, except when ${variables} are being used? I am guessing that the presence of the double quotes would require parsing of the String that an ordinary single-quoted String would not require. Therefore I would expect a very slight performance hit from the extra time looking for the presence of the ${}.

So, it would seem that it would be beneficial in general to have a convention to encourage the use single quotes, unless there is a specific advantage to using the double quotes. Am I off base?

Answer 1

is it more efficient to use single quotes, except when ${variables} are being used?

No. For the scenario where no ${variables} are used, they perform exactly the same. If there are no ${variables} in a double quoted String then the system does not create a GString. It creates a standard java.lang.String.

EDIT To Address A Separate Question Posted In A Comment Below:

It happens at compile time. The code below:

void someMethod(String a) {
    def s1 = "some string"
    def s2 = "some string with arg ${a}"
}
@groovy.transform.CompileStatic
void someOtherMethod(String a) {
    def s1 = "some string"
    def s2 = "some string with arg ${a}"
}

Compiles to this:

public void someMethod(String a)
{
    CallSite[] arrayOfCallSite = $getCallSiteArray();
    Object s1 = "some string";
    Object s2 = new GStringImpl(new Object[] { a }, new String[] { "some string with arg ", "" });
}

public void someOtherMethod(String a)
{
    String s1 = "some string";
    GString s2 = new GStringImpl(new Object[] { a }, new String[] { "some string with arg ", "" });
}