Spring Data ElasticSearch NullPointerException

Question

I have just started with Spring Data ElasticSearch. I have implemented my own repository, but I get a null pointer exception if I try to save an entity. I have got the following code, this is only some test code.

package org.test.elasticsearch.models;

import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;

@Document(indexName = "test", type = "book", shards = 1, replicas = 0)

public class Book {

@Id
private String id;
private String title;
private String author;

public Book(final String id, final String title, final String author) {
    this.id = id;
    this.title = title;
    this.author = author;
}

public String getId() {
    return this.id;
}

public void setId(final String id) {
    this.id = id;
}

public String getTitle() {
    return this.title;
}

public void setTitle(final String title) {
    this.title = title;
}

public String getAuthor() {
    return this.author;
}

public void setAuthor(final String author) {
    this.author = author;
}

}

package org.test.elasticsearch.configs;

import org.elasticsearch.node.NodeBuilder;
import org.test.elasticsearch.repositories.implementations.BookRepositoryImpl;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
import org.springframework.data.elasticsearch.core.ElasticsearchTemplate;
import org.springframework.data.elasticsearch.repository.config.EnableElasticsearchRepositories;

@Configuration
@EnableElasticsearchRepositories("org.test.elasticsearch.repositories")
public class ElasticsearchConfiguration {

@Bean
public ElasticsearchOperations elasticsearchTemplate() {
    final NodeBuilder nodeBuilder = new NodeBuilder();
    return new ElasticsearchTemplate(nodeBuilder.local(true).clusterName("elasticsearch").node().client());
}

@Bean
public BookRepositoryImpl bookRepositoryImplementation() {
    return new BookRepositoryImpl();
}

}

package org.test.elasticsearch.repositories;

import org.test.elasticsearch.models.Book;
import org.springframework.data.elasticsearch.repository.ElasticsearchCrudRepository;

public interface BookRepository extends ElasticsearchCrudRepository<Book, String>, BookRepositoryCustom {

    // query methods

}

package org.test.webapp;

import org.test.elasticsearch.models.Book;
import org.test.elasticsearch.models.Book.BookBuilder;
import org.test.elasticsearch.repositories.BookRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Test {

@Autowired
static BookRepository BookRepository;

public static void main(final String[] args) {
    SpringApplication.run(test.class, args);

    final Book testBook = new Book("12345", "TestTitle", "TestAuthor");
    BookRepository.save(testBook);
}

}

That's my code. And I get the following message after running my spring boot application.

Exception in thread "main" java.lang.NullPointerException
at org.test.webapp.test.main(Test.java:24)

Does anyone have an idea? And another question: When should I use ElasticsearchTemplate with IndexQuery over a custom repository to save my entities?

Answer 1

Your problem is, actually, with Spring Boot: you are not using it properly. Your Test class should look like this (no "static" access to BookRepository and done differently):

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.test.elasticsearch.models.Book;
import org.test.elasticsearch.repositories.BookRepository;

@Configuration
@ComponentScan(basePackages = {"org.test.elasticsearch.configs", "org.test.webapp"})
@EnableAutoConfiguration
public class Test implements CommandLineRunner {

    @Autowired
    private BookRepository bookRepository;

    @Override
    public void run(String... args) {
        final Book testBook = new Book("12345", "TestTitle", "TestAuthor");
        bookRepository.save(testBook);
    }

    public static void main(final String[] args) {
        SpringApplication.run(Test.class, args);
    }
}

Because, as I see it, you don't want to use a web application, so further you only need these dependencies in pom.xml. Nothing related to spring-boot-web:

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-elasticsearch</artifactId>
            <version>1.0.0.RELEASE</version>
        </dependency>