log4j2 java classes do not load application.properties entries with spring boot - spring-boot

Question

I am using log4j2(log4j-core and log4j-api) with Spring boot 2.2.0.RELEASE. I want to masking sensitive data inmy json payload in the logs. I have written a custom LogMaskingConverter which extends LogEventPatternConverter.
#Plugin(name = "LogMaskingConverter", category = "Converter")
#ConverterKeys({ "spi", "trscId" })
#Configuration
public class LogMaskingConverter extends LogEventPatternConverter {
#Value("${maskingFields}")
private String maskingFields;
protected LogMaskingConverter(String name, String style) {
super(name, style);
}
public static LogMaskingConverter newInstance(String[] options) {
return new LogMaskingConverter("spi", Thread.currentThread().getName());
}
#Override
public void format(LogEvent event, StringBuilder outputMessage) {
........
}
private String mask(String message) {
....
}
The problem is that the maskingFields does not get loaded from the application properties file.I read that log4j2 gets loaded before spring boot. Hence I have renamed my xml to log4j2-spring.xml so that spring boot is the first to intialise and load all the properties before it gets read via LogMaskingConverter.
Also below are my pom.xml dependencies related to log4j2
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
To summarise below code does not fetch any values:
#Value("${maskingFields}")
private String maskingFields;