I personally (anecdotal) feel that the Java world is a lot more formal; there are some Strong Opinions held in what "good" Java code is, which is missing in Javascript. This is in part due to great books like Effective Java, and in part due to editor / IDE support that will warn you and help you write great code - keep in mind that good IDE support has been missing in Javascript for years because of its lack of support for e.g. modules or namespaces, and its lack of Opinions.
Java's community has been Opinionated, whereas the JS community has been a lot more freeform. JQuery and NodeJS have been very influential in adding an opinion to the language; jquery by adding a kind of namespacing and scoping (also thanks to its predecessors / peers like YUI), NodeJS by adopting a module system (CommonJS) and centralized dependency management (NPM).
I came into JS via Java and while the lack of standards and rules / expectations was liberating, I was also missing it. It took a while before the best practices of Java made it into Javascript; in my experience, AngularJS was a big push for that, in that it was a much more opinionated way to structure your components and application - with a strong emphasis on (unit) testability.
Java's community has been Opinionated, whereas the JS community has been a lot more freeform. JQuery and NodeJS have been very influential in adding an opinion to the language; jquery by adding a kind of namespacing and scoping (also thanks to its predecessors / peers like YUI), NodeJS by adopting a module system (CommonJS) and centralized dependency management (NPM).
I came into JS via Java and while the lack of standards and rules / expectations was liberating, I was also missing it. It took a while before the best practices of Java made it into Javascript; in my experience, AngularJS was a big push for that, in that it was a much more opinionated way to structure your components and application - with a strong emphasis on (unit) testability.