Maven keeps overwriting my spring boot application.properties file? - maven

Question

I am using the open source messenger4j project to create a spring boog based Facebook bot:
https://github.com/messenger4j/messenger4j-spring-boot-quickstart-template
I am running on Ubuntu 12.x and using Maven 3.5.0.
I need to use nano to edit the application.properties file of the Maven project. I make my edits, which include changing the server port and a few other SSL related items and the application.properties file looks like this:
messenger4j.appSecret = ${MESSENGER_APP_SECRET}
messenger4j.verifyToken = ${MESSENGER_VERIFY_TOKEN}
messenger4j.pageAccessToken = ${MESSENGER_PAGE_ACCESS_TOKEN}
logging.level.com.github.messenger4j=INFO
server.port=1919
... <other edits> ...
I then save the file, exit nano, and "cat" that file to make sure the edits are still there. They are. However, when I compile and run the messenger4j app with this maven wrapper command line:
./mvnw spring-boot:run
I notice that the status messages tell me that the embedded Tomcat server is not listening on port 1919 but instead on the default port 8080. I reopen the application.properties file and I see only the default content again and see this:
messenger4j.appSecret = ${MESSENGER_APP_SECRET}
messenger4j.verifyToken = ${MESSENGER_VERIFY_TOKEN}
messenger4j.pageAccessToken = ${MESSENGER_PAGE_ACCESS_TOKEN}
logging.level.com.github.messenger4j=INFO
Does anyone know what is causing this and how to fix this? It appears that Maven is overwriting the application.properties file from some other source each time it compiles and runs (I'm guessing here)?
I saw a stack overflow post talking about a command line flag that tells maven not to overwrite the application.properties file. But if there is another source file that Maven is using (or should use) to auto-generate the application.properties file, I would like to edit that file instead of using that flag and stay with the usual expected workflow of a Maven project. I also would rather not pass a boat load of parameters on the mvnw command line either if I can help it.
UPDATE: Added pom.xml file.
Here is my pom.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.github.messenger4j</groupId>
<artifactId>messenger4j-spring-boot-quickstart-template</artifactId>
<version>1.0.2</version>
<packaging>jar</packaging>
<name>${project.groupId}:${project.artifactId}</name>
<description>Facebook Messenger Chatbot Template using Java, Spring Boot, and messenger4j</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.2.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.github.messenger4j</groupId>
<artifactId>messenger4j</artifactId>
<version>0.8.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
UPDATE: It turns out I was editing the ./target/classes/application.properties file instead of the file that Maven copies from to create that file. I'm referring to the true source file named ./src/main/resources/application.properties. Thank you dunni & Kyle.