17 ms·

Good to know, but 1-2 seconds is still very slow compared to a native app. I have an 8MB Go CLI application that can startup and print its help in .05 seconds,

Good to know, but 1-2 seconds is still very slow compared to a native app. I have an 8MB Go CLI application that can startup and print its help in .05 seconds, and even that is probably slow compared to a C or Rust equivalent.

deepsun 9y ago
Well, printing stuff is easy. Just tried: $ time java HelloWorld Hello, World real 0m0.088s user 0m0.088s sys 0m0.016s
- pebers 9y ago
  That's presumably not loading any libraries at all though - the time to being interactive (or just doing something useful) will get worse as more bytecode has to be decompressed and loaded.
  - pjmlp 9y ago
    > That's presumably not loading any libraries at all though Sure it is loading libraries, everything that System.out.println() depends on.
pjmlp 9y ago
Any savy Java developer knows how to AOT compile to native code, if that really matters. There are plenty of JDKs that support it, and even Oracle is finally adding support for it with Java 9, initially only for Linux x64. By Java 10 timeframe no one that only knows about OpenJDK and not the several other JDKs can state that Java starts slow vs C, because both will be AOT compiled to native code, loading native .so files.
- atomashpolskiy 9y ago
  Good point, but I wonder what size will the final binaries have, given that bytecode inflates significantly when translated to the machine code (there was a good discussion on HN recently about app sizes)
  - pjmlp 9y ago
    In any case smaller than Electron apps.
    - weberc2 9y ago
      Electron apps aren't really my standard for "reasonably sized CLI applications"...
- readittwice 9y ago
  From what I've seen Java/JVM AOT won't produce binary executables but shared libraries that will be loaded on startup by the JVM. When I first read about Java AOT-compilation I expected it to produce real executables that's why I think this is important to mention. But please correct me if I am wrong. So if this is true even with AOT compilation you still need the JVM as dependency (although I think you can get a minimal JVM in under 10MB). It also seems that the AOT compiled code needs to be recompiled on Java updates. Although I quite like Java and the JVM, I still wouldn't choose Java for writing simple command line tools. Nevertheless it is quite useful for improving startup for tools like Gradle or server applications. But sure, I also don't expect Java startup performance to be a problem in the mid- to long-run.
  - pjmlp 9y ago
    Correct, but that is no different than having to ship glibc.so or MSVCRT.dll alongside your application, specially if you want to be certain which version gets used. This is only relevant to Oracle's implementation though. Other JDKs do support static linking, as long as you restrain yourself from features that could require dynamic compilation. There was a talk at JVM Languages Summit about the current state of AOT compilation regarding Java 10. https://www.youtube.com/watch?v=n5DCg6M2MDM&index=11&list=PLX8CzqL3ArzXJ2EGftrmz4SzS6NRr6p2n https://www.youtube.com/watch?v=n5DCg6M2MDM&index=11&list=PL...
    - weberc2 9y ago
      I would rather ship glibc (8MB) or musl (.5MB) than the JVM (100s of MBs?), but it's not necessary given that nearly every target already has a libc. Also, Go programs don't depend on libc, and C and Rust can probably statically link against some libc in a pinch.
      - steveklabnik 9y ago
        Rust can use musl, yes.

deepsun 9y ago

Well, printing stuff is easy. Just tried: $ time java HelloWorld Hello, World real 0m0.088s user 0m0.088s sys 0m0.016s

pebers 9y ago
That's presumably not loading any libraries at all though - the time to being interactive (or just doing something useful) will get worse as more bytecode has to be decompressed and loaded.
- pjmlp 9y ago
  > That's presumably not loading any libraries at all though Sure it is loading libraries, everything that System.out.println() depends on.

pjmlp 9y ago

Any savy Java developer knows how to AOT compile to native code, if that really matters. There are plenty of JDKs that support it, and even Oracle is finally adding support for it with Java 9, initially only for Linux x64. By Java 10 timeframe no one that only knows about OpenJDK and not the several other JDKs can state that Java starts slow vs C, because both will be AOT compiled to native code, loading native .so files.

atomashpolskiy 9y ago
Good point, but I wonder what size will the final binaries have, given that bytecode inflates significantly when translated to the machine code (there was a good discussion on HN recently about app sizes)
- pjmlp 9y ago
  In any case smaller than Electron apps.
  - weberc2 9y ago
    Electron apps aren't really my standard for "reasonably sized CLI applications"...
readittwice 9y ago
From what I've seen Java/JVM AOT won't produce binary executables but shared libraries that will be loaded on startup by the JVM. When I first read about Java AOT-compilation I expected it to produce real executables that's why I think this is important to mention. But please correct me if I am wrong. So if this is true even with AOT compilation you still need the JVM as dependency (although I think you can get a minimal JVM in under 10MB). It also seems that the AOT compiled code needs to be recompiled on Java updates. Although I quite like Java and the JVM, I still wouldn't choose Java for writing simple command line tools. Nevertheless it is quite useful for improving startup for tools like Gradle or server applications. But sure, I also don't expect Java startup performance to be a problem in the mid- to long-run.
- pjmlp 9y ago
  Correct, but that is no different than having to ship glibc.so or MSVCRT.dll alongside your application, specially if you want to be certain which version gets used. This is only relevant to Oracle's implementation though. Other JDKs do support static linking, as long as you restrain yourself from features that could require dynamic compilation. There was a talk at JVM Languages Summit about the current state of AOT compilation regarding Java 10. https://www.youtube.com/watch?v=n5DCg6M2MDM&index=11&list=PLX8CzqL3ArzXJ2EGftrmz4SzS6NRr6p2n https://www.youtube.com/watch?v=n5DCg6M2MDM&index=11&list=PL...
  - weberc2 9y ago
    I would rather ship glibc (8MB) or musl (.5MB) than the JVM (100s of MBs?), but it's not necessary given that nearly every target already has a libc. Also, Go programs don't depend on libc, and C and Rust can probably statically link against some libc in a pinch.
    - steveklabnik 9y ago
      Rust can use musl, yes.