How to Set Environment Variables from Java

How do I set environment variables from Java?

(Is it because this is Java and therefore I shouldn't be doing evil nonportable obsolete things like touching my environment?)

I think you've hit the nail on the head.

A possible way to ease the burden would be to factor out a method

void setUpEnvironment(ProcessBuilder builder) {
    Map<String, String> env = builder.environment();
    // blah blah
}

and pass any ProcessBuilders through it before starting them.

Also, you probably already know this, but you can start more than one process with the same ProcessBuilder. So if your subprocesses are the same, you don't need to do this setup over and over.

How to add an environment variable in Java?

 Map<String, String> env = pb.environment();
 env.put("MV_ENV_VAR", "1");

would set MY_ENV_VAR=1. Before you invoke the Process by

Process p = pb.start();

export would only be interpreted by a shell.

See also ProcessBuilder

A full example:

public static void main(String[] args) throws IOException {

    ProcessBuilder pb = new ProcessBuilder("CMD", "/C", "SET");
    Map<String, String> env = pb.environment();
    env.put("MYVAR", "myValue");
    Process p = pb.start();
    InputStreamReader isr = new InputStreamReader(p.getInputStream());
    char[] buf = new char[1024];
    while (!isr.ready()) {
        ;
    }
    while (isr.read(buf) != -1) {
        System.out.println(buf);
    }
}

prints among other environment values:

MYVAR=myValue

This should prove that the created process uses the manipulated environment.

How to set environment variable in java

Simple example for how to set path with setx.exe in command line:

setx path "jdk bin path"

ex

setx path "C:\Program Files (x86)\Java\jdk1.7.0_04\bin"

try this on your code

like

    try {

        // using the Runtime exec method:
        Process p = Runtime.getRuntime().exec("setx path C:\Program Files (x86)\Java\jdk1.7.0_04\bin");

        BufferedReader stdInput = new BufferedReader(new
             InputStreamReader(p.getInputStream()));

        BufferedReader stdError = new BufferedReader(new
             InputStreamReader(p.getErrorStream()));

        // read the output from the command
        System.out.println("Here is the standard output of the command:\n");
        while ((s = stdInput.readLine()) != null) {
            System.out.println(s);
        }

        // read any errors from the attempted command
        System.out.println("Here is the standard error of the command (if any):\n");
        while ((s = stdError.readLine()) != null) {
            System.out.println(s);
        }

        System.exit(0);
    }
    catch (IOException e) {
        System.out.println("exception happened - here's what I know: ");
        e.printStackTrace();
        System.exit(-1);
    }

How to set JAVA environment variable in VS Code

In order to set environment variable for Spring boot application in VSCode, the recommended way is to create a launch.json file in .vscode folder of your project, then add the "env" section like the example below:

{
  "configurations": [
    {
      "type": "java",
      "name": "Spring Boot-DemoApplication<demo>",
      "request": "launch",
      "cwd": "${workspaceFolder}",
      "console": "internalConsole",
      "mainClass": "com.example.demo.DemoApplication",
      "projectName": "demo",
      "args": "",
      "env": {
        "PROJECT_NAME": "FOO_PROJECT"
      }
    }
  ]
}

How to set environment variables for Java

I suspect that the environment variable you're setting in your .bash_profile isn't getting picked up.

If you're running from Eclipse, you need to set environment variables manually on the Environment tab in the Run Configuration.

Go to Run -> Run Configurations..., find or create the run configuration for your app under Java Applications, go to the Environment tab and add your desired environment variables there.

Click the Run button and your program should print the environment variable as expected.

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