Azure Function in Java does not work locally

Path to Java for language worker java is set in configuration file worker.config.json in the installation directory azure-function-core-tools@3/%version/workers/java

{
    "description": {
        "language": "java",
        "extensions": [".jar"],
        "defaultExecutablePath": "/usr/bin/java",
        "defaultWorkerPath": "azure-functions-java-worker.jar",
        "arguments": ["-XX:+TieredCompilation -XX:TieredStopAtLevel=1 -noverify -Djava.net.preferIPv4Stack=true -jar", "%JAVA_OPTS%"]
    }
}

You need to change defaultExecutablePath from "%JAVA_HOME%/bin/java to the absolute path of your java executable (e.g. /usr/bin/java).

You can find the installation directory with readlink -f $(which func)

I started receiving this error after installing the latest versions of IDEA IntelliJ w/ Azure Toolkit for IntelliJ plugin, & Azure Core Tools v3 with and existing project on a new laptop.

The first error in the console when running the Azure Functions locally was:
Failed to start Worker Channel. Process fileName: %JAVA_HOME%/bin/java

So, for anyone getting this error using IntelliJ with Azure Functions, the JAVA_HOME can be set in the Run/Debug configuration for the Run Functions configuration.

Just add it to the App Settings, pointing to the correct location for Java root folder.

For example, on Windows if you've installed the Azure Supported SDK v11 (LTS version) (aka Zulu v11 for Azure) then it is installed into the Home path C:\Program Files\Zulu\zulu-11 whereby java.exe is located in the fully qualified path C:\Program Files\Zulu\zulu-11\bin\java.exe

So you would add the Key Value Pair: Key= "JAVA_HOME" Value = "C:\Program Files\Zulu\zulu-11"

As shown here:

i had this issue and found the solution provided by zeretbird almost worked for me. but i had to put JAVA_HOME and the path in my local.setting.json like so.

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "java",
    "StoreServiceendpoint": "blabla",
    "StoreServiceKey": "blabla",
    "JAVA_HOME": "/Library/Java/JavaVirtualMachines/jdk1.8.0_212.jdk/Contents/Home"
  }
}

In macOS, the variable name is $JAVA_HOME, but azure function still find the window format of %JAVA_HOME%. So it cannot find any java executive file in path.

So add JAVA_HOME in application run config setting.

If your are using core-tool@3 on a Mac you can also put the JAVA_HOME as App Setting in the intellij run configuration. https://i.stack.imgur.com/ED3YQ.png

Also: Using the which func does not work, you have to use the path of the actual binary located next to the wrapper that is found by which. It is located here (if you installed using npm): /usr/local/lib/node_modules/azure-functions-core-tools/bin/func

You can add JAVA_HOME in local.settings.json in the VS Code.

Here is an example. OS: WSL Ubuntu-20.04 Code editor: VS Code

{
  {
     "IsEncrypted": false,
     "Values": {
       "FUNCTIONS_WORKER_RUNTIME": "java",
       "JAVA_HOME": "/usr"
  }
}

Solution for macOS

1. Confirm the jvms installed, execute this in a terminal

/usr/libexec/java_home -V

2. Go to Run, then Edit Configurations. Edit the Run Function in Azure Functions. In App Settings add JAVA_HOME as key and the path to the JVM obtained in 1)

You may try "Remote Development" in VS code as a quicker and easier option. Please refer to the tutorial here

Here is one example of java dev environment You will have to install Remote Development extension and would suggest Remote-Container. Try sample for Java.

https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers&WT.mc_id=azurespringcloud-github-judubois

https://github.com/microsoft/azure-spring-cloud-training/blob/master/00-setup-your-environment/AlternateSetup.md#preparing-visual-studio-code

https://code.visualstudio.com/docs/remote/faq#_remote-containers

I am using windows 10 professional and using azure function using IntelliJ IDEA 2020.2.3 (Community Edition) Build #IC-202.7660.26, built on October 6, 2020. I ran into the same issue .

Apparently it is looking for environment variable JAVA_HOME. I have added the in windows environment variables . After setting this up I was able to run the java function locally.

Generally %JAVA_HOME% notation is used for windows operating system. It might be a bug or try setting JAVA_HOME at profile level and make sure it points to right JDK .

This was just a fluke , somehow it worked . Hope it works for you too .