title: @Cacheble annotation on no parameter method
body: <p>I want to have <code>@Cacheable</code> annotation on method with no parameter. In that case, I use @Cacheable as follows </p>
  
  <pre><code>@Cacheable(value="usercache", key = "mykey")
  public string sayHello(){
      return "test"
  }
  </code></pre>
  
  <p>However, when I call this method, it doesn't get executed and it get exception as below</p>
  
  <blockquote>
    <p>org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): Property or field 'mykey' cannot be found on object of type 'org.springframework.cache.interceptor.CacheExpressionRootObject' - maybe not public?</p>
  </blockquote>
  
  <p>Please suggest.</p>