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Really Small Java Apps

august.nagro.us

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Re: Really Small Java Apps

#11

Post by taude »

sgt wrote: post #2

I get Docker and I use it, but it does bother me that one bundles the JDK along with the docker image. Such a waste of space. I like this idea, I hope it gets more traction. In terms of deployment of Java apps, we've found that Nomad works really well as it doesn't need a full Docker image (or equivalent) like Docker, Kubernetes etc. In Nomad you just make sure the worker node has the JDK, and then you specify the .j…

I don't see what the issue is with space/size having the JDK in a docker issue layer vs installing through ansible/chef later (or whenever it is you're doing). Docker images are layered, and by including a pinned version of the JVM that's baked into a core Docker stack for your org that's been security hardened, tested, etc, seems like it's better than taking the time to install a JVM every time during deployment of the worker node.

EDIT: checking out Nomad now, since we have used other Hashicorp prods in the past...

Re: Really Small Java Apps

#12

Post by userbinator »

I thought this article would be about something like https://en.wikipedia.org/wiki/Java_4K_Game_Programming_Conte... but it's more appropriately "Really Small JVM".

For a simple project requiring java.net.http, using these steps produced a 23MB jlink image

23MB may seem tiny today, but depending on what that "simple project" does, in absolute terms it's still twenty-three million bytes. For comparison, a full installation of Windows 3.11 is roughly that size too, not compressed. As the saying goes, "there's still plenty of room at the bottom."

Re: Really Small Java Apps

#13

Post by bluedino »

userbinator wrote: post #12

I thought this article would be about something like https://en.wikipedia.org/wiki/Java_4K_Game_Programming_Conte... but it's more appropriately "Really Small JVM". For a simple project requiring java.net.http, using these steps produced a 23MB jlink image 23MB may seem tiny today, but depending on what that "simple project" does, in absolute terms it's still twenty-three million bytes. For comparison, a full install…

To be fair, Windows at that time was a pretty simple 16-bit operating system, and didn't even support networking until you added Winsock or WFW 3.11.

It didn't really support much of anything until you started adding lots of other DLL's and libraries

Re: Really Small Java Apps

#14

Post by thrower123 »

userbinator wrote: post #12

I thought this article would be about something like https://en.wikipedia.org/wiki/Java_4K_Game_Programming_Conte... but it's more appropriately "Really Small JVM". For a simple project requiring java.net.http, using these steps produced a 23MB jlink image 23MB may seem tiny today, but depending on what that "simple project" does, in absolute terms it's still twenty-three million bytes. For comparison, a full install…

That'd be 16 floppy disks, or roughly a quarter of the hard disk space on my first PC clone. Or nearly ten Dooms!

Re: Really Small Java Apps

#15

Post by jcollins »

I've found a combination of Spring Boot executable jar + a small jlink built JRE runtime packaged next to the executable jar works fairly well.

Our zipped distribution is 50mb. Uncompressed the executable is 26mb and the runtime is 75mb.

I'd love for it to be smaller but I can't complain. This also makes solving for Linux, macOS, and Windows pretty trivial. They each get their own zip with packaged runtime.

Re: Really Small Java Apps

#16

Post by Longwelwind »

sgt wrote: post #2

I get Docker and I use it, but it does bother me that one bundles the JDK along with the docker image. Such a waste of space. I like this idea, I hope it gets more traction. In terms of deployment of Java apps, we've found that Nomad works really well as it doesn't need a full Docker image (or equivalent) like Docker, Kubernetes etc. In Nomad you just make sure the worker node has the JDK, and then you specify the .j…

I'm not sure this is the issue you are referencing, but you can use multi-stage Docker image builds to avoid bundling the JDK in the final Docker image:

  FROM openjdk:jdk AS build
  
  COPY . .
  RUN mvn package

  FROM openjdk:jre

  COPY --from=build ./somepath/app.jar .

  CMD java app.jar
The first stage (defined by the first FROM) is only used to build the ".jar", the second stage will only contain the JRE and the ".jar" copied from the first stage.

Re: Really Small Java Apps

#17

Post by Koshkin »

bluedino wrote: post #13
userbinator wrote: post #12

I thought this article would be about something like https://en.wikipedia.org/wiki/Java_4K_Game_Programming_Conte... but it's more appropriately "Really Small JVM". For a simple project requiring java.net.http, using these steps produced a 23MB jlink image 23MB may seem tiny today, but depending on what that "simple project" does, in absolute terms it's still twenty-three million bytes. For comparison, a full install…

To be fair, Windows at that time was a pretty simple 16-bit operating system, and didn't even support networking until you added Winsock or WFW 3.11. It didn't really support much of anything until you started adding lots of other DLL's and libraries

Well, simple or not - the first UNIX needed 24 kilobytes of RAM. (Not sure about the disk space - probably 10x that if you count all the utilities.)

Re: Really Small Java Apps

#18

Post by [deleted] »

hmottestad wrote: post #7
manojlds wrote: post #3

Is GraalVM a good option for this?

Yes and no. Graal Native Image doesn’t work for spring, since some of the jvm functionality wrt. class loading don’t work yet (I think). Also native image has lower throughput due to the lack of profile driven code optimizations.

[deleted]

Re: Really Small Java Apps

#19

Post by hyperpallium »

userbinator wrote: post #12

I thought this article would be about something like https://en.wikipedia.org/wiki/Java_4K_Game_Programming_Conte... but it's more appropriately "Really Small JVM". For a simple project requiring java.net.http, using these steps produced a 23MB jlink image 23MB may seem tiny today, but depending on what that "simple project" does, in absolute terms it's still twenty-three million bytes. For comparison, a full install…

Things That Turbo Pascal is Smaller Than https://prog21.dadgum.com/116.html

Re: Really Small Java Apps

#20

Post by dashwav »

Longwelwind wrote: post #16
sgt wrote: post #2

I get Docker and I use it, but it does bother me that one bundles the JDK along with the docker image. Such a waste of space. I like this idea, I hope it gets more traction. In terms of deployment of Java apps, we've found that Nomad works really well as it doesn't need a full Docker image (or equivalent) like Docker, Kubernetes etc. In Nomad you just make sure the worker node has the JDK, and then you specify the .j…

I'm not sure this is the issue you are referencing, but you can use multi-stage Docker image builds to avoid bundling the JDK in the final Docker image: FROM openjdk:jdk AS build COPY . . RUN mvn package FROM openjdk:jre COPY --from=build ./somepath/app.jar . CMD java app.jar The first stage (defined by the first FROM) is only used to build the ".jar", the second stage will only contain the JRE and the ".jar" copied…

Anything after Java 9 would have to use the jlink method, as with the new modules system, there is no longer a distinction between the JDK and JRE.

The problem is most 3rd party libraries aren't ready for the modules switchover, so for anyone using those libraries, you are stuck with having either a 3-400mb docker image or using jlink

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