Spring Boot 1.5.6 auto reload not working

Question

I am working with Spring Boot application. I want to auto reload feature of spring boot so I can get java code change effect on my application but it's not working for me. Below are the details of my application:

Spring Boot Version: 1.5.6.RELEASE
Type: Maven
Packaging: War
IDE: STS (Spring Tool Suite)
Java Version: 1.8.0_144
OS: Ubuntu 16.04.3 LTS

I have added following dependency for auto reloading.

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
</dependency>

Please help me to fix this issue.