JVM startup for `java -version` is around 150ms on my machine:

    $ time java -version
    openjdk version "11.0.1" 2018-10-16
    OpenJDK Runtime Environment 18.9 (build 11.0.1+13)
    OpenJDK 64-Bit Server VM 18.9 (build 11.0.1+13, mixed mode)

    real 0m0.159s
    user 0m0.116s
    sys 0m0.052s

This is how long it takes for a program like git to do actual work. Once you start running an actual program like Maven, it blows up to 500ms for `mvn -version`:

    $ time  mvn -version > /dev/null

    real 0m0.570s
    user 0m0.431s
    sys 0m0.145s

Bazel takes 150ms to do nothing:

    $ time bazel --version > /dev/null

    real 0m0.144s
    user 0m0.028s
    sys 0m0.063s

As a baseline, make takes under 30ms to do nothing:

    $ time make -version > /dev/null

    real 0m0.025s
    user 0m0.002s
    sys 0m0.016s

Seems similar on my system. Some more comparisions:

Waf written in Python:

    $ time ./waf --version >/dev/null

    real 0m0,068s
    user 0m0,056s
    sys 0m0,012s

Ninja written in C++:

    $ time ninja --version >/dev/null

    real 0m0,001s
    user 0m0,001s
    sys 0m0,000s

Java 13 takes 97ms on Windows 10, and I haven't bothered to produce a Java native image before attempting it.

    PS C:\Workdir> Measure-Command { java -version }
    openjdk version "13" 2019-09-17
    OpenJDK Runtime Environment (build 13+33)
    OpenJDK 64-Bit Server VM (build 13+33, mixed mode, sharing)


    Days              : 0
    Hours             : 0
    Minutes           : 0
    Seconds           : 0
    Milliseconds      : 97
    Ticks             : 975572
    TotalDays         : 1.12913425925926E-06
    TotalHours        : 2.70992222222222E-05
    TotalMinutes      : 0.00162595333333333
    TotalSeconds      : 0.0975572
    TotalMilliseconds : 97.5572

About 60 ms more than make.

Hurray Make still wins, now what are we going to do with those 60ms... /s

FWIW, I don't think "java -version" is a good benchmark of java startup time - why should it start up the JVM just to print the version?

I think that measuring anything less than 1s for CLI is silly, school playground measuring competition.

The original comment was "JVM startup is sub-second. Still not great for e.g. small command line utilities, but completely fine otherwise."

For tooling it matters. Some scripts will have backticks and $() and each use of these could be up to a second and be acceptable? Not really. And if you want to run a command like `go fmt` every time you save a file in $EDITOR then you want it to be fast. Maybe when we use the Language Server Protocol everywhere, it will be a different world. But a lot of editors shell out for these features still - and you would never dream of shelling out to e.g. `mvn dependency:tree` because it's too slow.

Unless I am missing something, 97ms looks pretty much sub-second to me.

With Graal AOT you can make command line utilities that start on the order of 0.008s

https://github.com/graalvm/graalvm-demos/tree/master/java-ko...

> make takes under 30ms to do nothing:

But in large code bases, make can take several seconds to do nothing, depending on the number of `$(shell find)`.

Whereas Bazel's time remains constant. Could it have been constantly 30ms instead of 150ms?

Sure. But that's nowhere near to being a problem for the usual code bases Bazel operates on.

$ time ./java -version openjdk version "14-ea" 2020-03-17 OpenJDK Runtime Environment (build 14-ea+19-824) OpenJDK 64-Bit Server VM (build 14-ea+19-824, mixed mode, sharing)

real 0m0.074s user 0m0.063s sys 0m0.025s