title: The web application [ROOT] appears to have started a thread named [pollingConfigurationSource] but has failed to stop it. Memory leak
body: <p>Hi i am getting memory leak error while running project. I am using <code>spring boot</code> + <code>quards scheduler</code> + <code>liquibase</code> + <code>postgreSQL 9.6</code>. These are technologies we are using.</p>
  
  <p><strong>Error:</strong></p>
  
  <pre><code>12018-10-15 11:43:19.005  WARN [billing,,,] 19152 --- [ost-startStop-1] o.a.c.loader.WebappClassLoaderBase       : The web application [ROOT] appears to have started a thread named [pollingConfigurationSource] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
   sun.misc.Unsafe.park(Native Method)
   java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
   java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
   java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
   java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
   java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
   java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
   java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
           java.lang.Thread.run(Thread.java:748)
  </code></pre>
  
  <p>and my configuration code is:</p>
  
  <pre><code>package com.xyz.api;
  
  @Slf4j
  @XyzService
  @EnableWebSecurity
  @EnableResourceServer
  @EnableGlobalMethodSecurity( prePostEnabled = true )
  public class BApplication extends ResourceServerConfigurerAdapter implements WebMvcConfigurer
  {
      public static void main( String[] args )
      {
          SpringApplication.run( BApplication.class, args );
      }
  
      @Override
      public void configure( ResourceServerSecurityConfigurer resources )
      {
          resources.resourceId( "xxxx" );
      }
  
      @Override
      public void configure( HttpSecurity http ) throws Exception
      {
          http.authorizeRequests()
              .antMatchers( "/" ).permitAll()
              .antMatchers( "/docs/**" ).permitAll()
              .antMatchers( "/actuator/health" ).permitAll() // can we tighten this up?
              .anyRequest().authenticated(); //individual services use annotations
      }
  
      @Override
      public void addViewControllers( ViewControllerRegistry registry )
      {
          registry.addViewController( "/" ).setViewName( "forward:/docs/index.html" );
      }
  
      @Bean
      public Clock clock()
      {
          return Clock.systemUTC();
      }
  
      @Bean
      public RestTemplate restTemplate( RestTemplateBuilder builder )
      {
          return builder.build();
      }
  }
  </code></pre>
  
  <p>Actually this work fine earlier but suddenly it give error at deployment. Help me out to solve this issue.</p>
  
  <p>I also referred: <a href="https://stackoverflow.com/questions/49126078/memory-leak-issue-with-spring-cloud-starter-hystrix-and-spring-cloud-starter-arc">Memory Leak Issue with spring-cloud-starter-hystrix and spring-cloud-starter-archaius integration</a>
  But not getting any solution on this.</p>