An application can read 3 types of value from the application.properties file.
application.properties
my.name=kelly
my.dbConnection ={connection_srting:'http://localhost:...',username:'benz',password:'pwd'}
@Value("${my.name}")
private String name;
@Value("#{${my.dbConnection}}")
private Map<String,String> dbValues;
If you don't have a property in application.properties then you can use default value
@Value("${your_name : default value}")
private String msg;