title: How to use Short datatype with @Cacheable?
body: <p>I'm trying to cache <code>Short</code> value with <code>@Cacheable</code>.</p>
  
  <pre><code>@EnableAutoConfiguration
  @EnableCaching
  public class Config {
      @Bean
      public CacheManager cacheManager() { 
          return new ConcurrentMapCacheManager(); 
      }
  }
  
  @Service
  public class MyCacheService {
      @Cacheable("testcache")
      public Short getId(String name) {
          return 1;
      }
  }
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>java.lang.NullPointerException
      at org.springframework.cache.interceptor.AbstractCacheResolver.resolveCaches(AbstractCacheResolver.java:78) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.cache.interceptor.CacheAspectSupport.getCaches(CacheAspectSupport.java:216) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.cache.interceptor.CacheAspectSupport$CacheOperationContext.&lt;init&gt;(CacheAspectSupport.java:565) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.cache.interceptor.CacheAspectSupport.getOperationContext(CacheAspectSupport.java:229) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.cache.interceptor.CacheAspectSupport$CacheOperationContexts.&lt;init&gt;(CacheAspectSupport.java:508) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:302) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:61) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.6.RELEASE.jar:4.2.6.RELEASE]
      at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655) ~[spring-aop-4.2.6.RELEASE.jar:4.2.6.RELEASE]
  </code></pre>
  
  <p>This is thrown because <code>cacheManager</code> is <code>null</code> in <code>AbstractCacheResolver</code>. But why?</p>