----- Mail original ----- > De: "Jochen Theodorou" <blackd...@gmx.org> > À: dev@groovy.apache.org > Envoyé: Mercredi 22 Février 2017 22:49:01 > Objet: Re: Help with pitching Groovy and Grails
> On 21.02.2017 22:51, Raviteja Lokineni wrote: >> Hi Devs, >> >> I was trying to pitch using Grails for one of our projects and the >> discussions always ended up with "using reflections in JVM is slow >> period". I am not knowledgeable to defend the internals of either Groovy >> or Grails, need some help on this topic. >> >> The only selling point that they identified was GORM. >> >> I thought this might be the time to ask the developer community. I am >> trying to gather some points on using Grails over a Spring boot application. >> >> Also, can anyone help me understand how Groovy runtime optimizations are >> applied on a high level and if it will affect the runtime performance. > > don´t forget in Grails you have a very thin Groovy layer over Java code. > That little Groovy makes a big difference in the usage, but not in the > performance part. And depending on what you do Groovy can be pretty fast > (Java 10s, Groovy 15s for example). That might be related to Groovy > actually not using Reflection where possible... well, of course I should > also mention that for a example a method call using reflection use to be > like factor 30 slower compared with a direct method call using Java. But > that is no longer true for a long time. yes, 30x was a long long time ago, i think before 1.4.2. The last time the reflection code was touched for speed update was during the Java 7 timeframe. > And then in Groovy we use runtime code generation to avoid Reflection and > optionally you could > also use the indy port, which is based on invokedynamic (the same one > that is used for method calls for lambdas) which can be pretty fast. And > if that is not enough, you can still use the static compiler to be > around the same level as Java. Technically, invokedynamic is used from creating the lambda not for calling it, because after creation it's more like a plain reference on an object that implement a functional interface, so it can be called like a plain old interface. There has been a prototype to use invokedynamic to call the lambda but performance was identical to an interface call so it was not integrated because invokedynamic makes the startup a little slower (like reflection does). In the jdk 9, invokedynamic is used when you do a concatenation with + because invokedynamic is faster that using a chain of plain old Java calls to StringBuilder.append(). > > bye Jochen Rémi
