Bug 140160 [Field Assist] - JAVADOC ONLY- FieldDecorationRegistry API should specify that null dec description is allowed
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/FieldDecorationRegistry.java
.getString("FieldDecorationRegistry.errorMessage"), 
				IMG_DEC_FIELD_ERROR, imageRegistry);
		getDefault().registerFieldDecoration(DEC_WARNING, null,
				IMG_DEC_FIELD_WARNING, imageRegistry);
		getDefault()
				.registerFieldDecoration(
						DEC_REQUIRED,
						JFaceResources
								.getString("FieldDecorationRegistry.requiredFieldMessage"), 
						IMG_DEC_FIELD_REQUIRED, imageRegistry);
	}
	/*
	 * Data structure that holds onto the decoration image info and description,
	 * and can produce a decorator on request.
	 */
	class Entry {
		private String description;
		private String imageId;
		private ImageRegistry imageRegistry;
		private Image image;
		private FieldDecoration decoration;
		Entry(String description, String imageId, ImageRegistry registry) {
			this.description = description;
			this.imageId = imageId;
			this.imageRegistry = registry;
		}
		Entry(String description, Image image) {
			this.description = description;
			this.image = image;
		}