SpringBootBackendApplication.java:3: error: package org.springframework.boot does not exist - spring

Question

When trying to run SpringBoot application, I get the following errors:
SpringBootBackendApplication.java:3: error: package org.springframework.boot does not exist
import org.springframework.boot.SpringApplication;
^
SpringBootBackendApplication.java:4: error: package org.springframework.boot.autoconfigure does not exist
import org.springframework.boot.autoconfigure.SpringBootApplication;
^
SpringBootBackendApplication.java:6: error: cannot find symbol
#SpringBootApplication
^
symbol: class SpringBootApplication
This also happened with another project of mine. Does the project have to be run with Maven? If not, what could be causing an error such as this? Is the code even supposed to be executable in its current state?
My Pom File:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.7.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.ourlibrary</groupId>
<artifactId>spring-boot</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>spring-boot-backend</name>
<description>Our Library </description>
<properties>
<java.version>11</java.version>
</properties>
<properties>
<start-class>com.ourlibrary.springboot.Application</start-class>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
My Main Method:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class SpringBootBackendApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootBackendApplication.class, args);
}
}