• Description:
  This task helps you to automate a Java workflow with Terraform. Terraform will create a project folder, write a Hello.java source file, compile it with javac, and run it with java — all via Terraform resources and provisioners. It’s a good demonstration of using local-exec, null_resource, and local_file for local automation and scripting.
•  Prerequisites:
   Terraform installed and available in your PATH.
   Java JDK (javac and java) installed and available in your PATH.
   JSON-based settings for containers
   A Unix-like shell (commands shown for Linux/macOS; Windows PowerShell would require small changes).

•  Step 1 — Create project directory
   Create directory and navigate into it:

  mkdir java-terraform
  cd java-terraform
      

•  Step 2 — Create main.tf
   Create the Terraform file:

  nano main.tf
      

   Paste the following content:

  terraform {
    required_providers {
      local = {
        source = "hashicorp/local"
      }
    }
  }
  
  provider "local" {}
  
  # 1. Create a folder for Java project
  resource "null_resource" "create_folder" {
    provisioner "local-exec" {
      command = "mkdir -p myjava"
    }
  }
  
  # 2. Create the Java file
  resource "local_file" "java_program" {
    depends_on = [null_resource.create_folder]
  
    filename = "${path.module}/myjava/Hello.java"
  
    content = <<-EOF
      public class Hello {
          public static void main(String[] args) {
              System.out.println("Hello from Terraform + Java!");
          }
      }
    EOF
  }
  
  # 3. Compile the Java code
  resource "null_resource" "compile_java" {
    depends_on = [local_file.java_program]
  
    provisioner "local-exec" {
      command = "javac myjava/Hello.java"
    }
  }
  
  # 4. Run the Java program
  resource "null_resource" "run_java" {
    depends_on = [null_resource.compile_java]
  
    provisioner "local-exec" {
      command = "java -cp myjava Hello"
    }
  }
      

•  Step 3 — Initialize Terraform
   Initialize Terraform:

  terraform init
      

   This downloads any provider plugin (local provider) and prepares the working directory.
•  Step 4 — Validate configuration
   Validate Terraform files:

  terraform validate
      

   Ensures your HCL is syntactically valid.
•  Step 5 — Apply the configuration
   Apply Terraform:

  terraform apply -auto-approve
      

   Terraform will:
   create myjava/ folder,
   write myjava/Hello.java,
   run javac myjava/Hello.java to create Hello.class,
   run java -cp myjava Hello and print the program output to your terminal.
  
   Expected terminal output (part of apply’s provisioning output):

  null_resource.run_java (local-exec): Hello from Terraform + Java!
  Apply complete! Resources: 4 added, 0 changed, 0 destroyed.
      

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