LibraryLocalServiceImpl file with method calling custom sql finder

LibraryLocalServiceImpl.java

package me.rkg.plugins.service.impl;

import java.util.List;

import me.rkg.plugins.model.Author;
import me.rkg.plugins.model.Book;

import me.rkg.plugins.service.base.LibraryLocalServiceBaseImpl;

/**
 * The implementation of the library local service.
 *
 * <p>
 * All custom service methods should be put in this class. Whenever methods are added, rerun ServiceBuilder to copy their definitions into the {@link me.rkg.plugins.service.LibraryLocalService} interface.
 *
 * <p>
 * This is a local service. Methods of this service will not have security checks based on the propagated JAAS credentials because this service can only be accessed from within the same VM.
 * </p>
 *
 * @author Ravi Kumar Gupta
 * @see me.rkg.plugins.service.base.LibraryLocalServiceBaseImpl
 * @see me.rkg.plugins.service.LibraryLocalServiceUtil
 */
public class LibraryLocalServiceImpl extends LibraryLocalServiceBaseImpl {
	/*
	 * NOTE FOR DEVELOPERS:
	 *
	 * Never reference this interface directly. Always use {@link me.rkg.plugins.service.LibraryLocalServiceUtil} to access the library local service.
	 */
	
	public List<Object> getBookDetailsByAuthorAndTitle(String authorName, String title){
		List<Object[]> objects = libraryFinder.findByAuthorAndTitle(authorName, title, -1, -1);
		for(Object[] objs : objects){
			System.out.println(objs.length);
			for(int i=0;i<objs.length;i++){
				if(objs[i] instanceof Book){
					System.out.println("Object is instance of Book");
				}
				if(objs[i] instanceof Author){
					System.out.println("Object is instance of Author");
				}
			}
		}
		return null;
	}
}