Could not resolve placeholder 'spring.datasource.oracle.url' in value

This error message is typically seen in a Spring application when a placeholder is not properly resolved. In this case, the placeholder 'spring.datasource.oracle.url' is not being resolved correctly.

To resolve this issue, make sure that the property 'spring.datasource.oracle.url' is defined in your application's configuration file (e.g. application.yml or application.properties) and that its value is properly set. Additionally, make sure that your application is correctly configured to read properties from the configuration file.

For example, in application.yml, you might have:

spring:
  datasource:
    oracle:
      url: jdbc:oracle:thin:@//localhost:1521/orcl
      username: myuser
      password: mypassword

If you are using Spring Boot, you can also check that your application is correctly configured to use the appropriate configuration file. By default, Spring Boot looks for an application.yml or application.properties file in the classpath. If your configuration file is named differently or located in a different directory, you will need to specify this in your application's configuration or command line arguments.