Why? IIUC it implies that they _don't_ have their own string implementations. They get the benefit of Java JDK's string implementation (and JVM optimization the

Why? IIUC it implies that they _don't_ have their own string implementations. They get the benefit of Java JDK's string implementation (and JVM optimization thereof) for free. If they had their own string implementations, they'd be unable to use this optimization until it's publicly available.