I'm surprised that surprises you, JavaScript is heavily optimized for startup and Java has a very long history of being slow to load. How many cli utilities are built on Java/JVM? JVM's speed doesn't show until it has warmed up, that's why it's used for servers.
Sure, I know Sun's JVM is infamous for poor startup performance. But Dalvik is different, isn't it? Not to mention ART, introduced in ANdroid 5.0, where Dex bytecode is AOT-compiled to native code.
