Code optimization suggestions

[noobyu6]

Hi,

I find that the private field hasAnnotations at Line 287 in the file 'guice/core/src/com/google/inject/internal/Annotations.java ' on the master branch is only assigned and used in the field cache. Therefore, this field can be removed from the class, and become an input parameter in the field cache. This transformation will normally reduce memory usage and improve readability of your code.I will be happy if this transformation is helpful.

// line 287 this field can be removed from the class
private CacheLoader<Class<? extends Annotation>, Boolean> hasAnnotations = 
        new CacheLoader<Class<? extends Annotation>, Boolean>() {
          @Override
          public Boolean load(Class<? extends Annotation> annotationType) {
            for (Annotation annotation : annotationType.getAnnotations()) {
              if (annotationTypes.contains(annotation.annotationType())) {
                return true;
              }
            }
            return false;
          }
        };
// start 
final LoadingCache<Class<? extends Annotation>, Boolean> cache =
        CacheBuilder.newBuilder().weakKeys().build(new CacheLoader<Class<? extends Annotation>, Boolean>() {
          @Override
          public Boolean load(Class<? extends Annotation> annotationType) {
            for (Annotation annotation : annotationType.getAnnotations()) {
              if (annotationTypes.contains(annotation.annotationType())) {
                return true;
              }
            }
            return false;
          }
        });
// end

    final LoadingCache<Class<? extends Annotation>, Boolean> cache =
        CacheBuilder.newBuilder().weakKeys().build(hasAnnotations);