Throughput in Java can be quite high, and latency can be quite low. You still occasionally get latency spikes from the GC, but these days that's not so bad. (If you are extremely latency sensitive, stick to C++).
Dependency injection frameworks are your bread-and-butter in server-side Java, and some can take a while to grok, but Java can be very productive after the chosen framework "clicks" for you. Typically, this means you'll be writing constructors or factory classes that construct your dependencies per request. The way you wire your factories into the system differs by framework, but it often involves using Java's annotation syntax.
Not having to worry about memory management is a huge win for productivity over C++. Likewise, constructors in Java are much more sane than in C++.
Classical object-oriented programming is intuitive, and Java tends towards the "one obvious way to do something" paradigm. I find it pretty easy to hop into legacy code bases, if I already know the framework being used. The collections API in the standard library is one of the best classical OO APIs out there.
The JVM provides great visibility into the performance of your system. A lot of instrumentation comes "for free".
I'm not sure where you get the "dirty" and "bloated" feeling from. By any definition I can think of for those words, Python would be in the same bucket.
Without DI, there's too much flexibility in how objects get constructed. If you want to add new functionality to a legacy code base, it can be difficult to track down the different integration points and slow to plumb through your dependencies. These projects can turn into spaghetti very quickly.
DI solves this with a simple recipe: define your functionality, define your dependencies, wire it up to the injector.
The pattern is useful in all OO languages, Python and C++ included.
Dependency injection frameworks are your bread-and-butter in server-side Java, and some can take a while to grok, but Java can be very productive after the chosen framework "clicks" for you. Typically, this means you'll be writing constructors or factory classes that construct your dependencies per request. The way you wire your factories into the system differs by framework, but it often involves using Java's annotation syntax.
Not having to worry about memory management is a huge win for productivity over C++. Likewise, constructors in Java are much more sane than in C++.
Classical object-oriented programming is intuitive, and Java tends towards the "one obvious way to do something" paradigm. I find it pretty easy to hop into legacy code bases, if I already know the framework being used. The collections API in the standard library is one of the best classical OO APIs out there.
The JVM provides great visibility into the performance of your system. A lot of instrumentation comes "for free".
I'm not sure where you get the "dirty" and "bloated" feeling from. By any definition I can think of for those words, Python would be in the same bucket.