GString performance

Question

If I need plain string in Groovy, does using double-quoted literals make any influence on performance?

For instance:

def plainString = 'Custom string'
def gString = "Custom string"

In my understanding, plain String should be faster because during runtime there are no searches for specific characters and substitutions.

Answer 1

From the Groovy Language Specification:

Double quoted strings are plain java.lang.String if there’s no interpolated expression, but are groovy.lang.GString instances if interpolation is present.

Therefore, feel free to use double quotes or single quotes: they will result in the same type of object. The difference will be when you have a $ in the double-quoted string. But by then, we are talking semantics, not performance.