Azure environment variable not working: "Factory method 'dataSource' threw exception with message: URL must start with 'jdbc' "

I tried setting up environment variables on application.properties with the ${VARIABLE_NAME} and then in the azure configuration I set up the key value pair. But it doesn't seem to work. I also tried running System.getenv before the application starts, but that didn't do much. So I keep getting the error that the URL must start with jdbc since its not using the env variable I set.

The line below is from the application.properties:

spring.datasource.url=${DB_CONNECTION_STRING}

and in azure i set an application setting in the configuration section
for DB_CONNECTION_STRING with the value of jdbc.....

Then I even tried to set it as a connection string in the azure config as well
with the 'SQLAZURECONNSTR' prefix, and still nothing works.

Then I even tried this before main:
String dbConnectionString = System.getenv("DB_CONNECTION_STRING");

Not sure if that does anything.

>I also tried running System.getenv before the application starts, but that didn't do much.

I have tried to reproduce with System.getenv() method in my environment, it worked as expected and could achieve the expected results.

To access the env variables in your code, create a variable in App Service->Settings-> Configuration and assign its value as shown below:

Below is the code snippet of my sample Controller class to fetch the specified env variable:

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public  class  AzureAppController  {
	@GetMapping(value  =  "/my-var")
	public  String  getMyVar()  {
		return  "The value of MY_VAR is: "  +  System.getenv("MY_VAR");
	}
}

Response:

Before Setting the Environment Variable:

After Setting the Environment Variable: