Programming Posts

Error “Can not write a field name, expecting a value;” while Writing JSON on Spring MVC

The error started since i upgraded my jackson library, somehow it never happen before. This is my full stacktrace

com.fasterxml.jackson.core.JsonGenerationException: Can not write a field name, expecting a value
	com.fasterxml.jackson.core.JsonGenerator._reportError(JsonGenerator.java:1649)
	com.fasterxml.jackson.core.json.UTF8JsonGenerator.writeFieldName(UTF8JsonGenerator.java:186)
	com.edw.test.jackson.TestSerializer.serialize(TestSerializer.java:27)
	com.edw.test.jackson.TestSerializer.serialize(TestSerializer.java:19)
	com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
	com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1387)
	com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:889)
	org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:292)
	org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:106)
	org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:231)
	org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:174)
	org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:81)
	org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:113)
	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
	org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)

Looks like this error happen on my custom json serializer,

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="false">
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" p:objectMapper-ref="testObjectMapper"/>
        </mvc:message-converters>
    </mvc:annotation-driven>
    
    <context:component-scan base-package="com.edw.test.jackson"/>
</beans>

And this is the content of my objectMapper java class,

package com.edw.test.jackson;

import com.edw.test.jackson.bean.Test;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.module.SimpleModule;
import org.springframework.stereotype.Component;

@Component
public class TestObjectMapper extends ObjectMapper {
    public TestObjectMapper() {
        super();
        
        SimpleModule module = new SimpleModule();
        module.addSerializer(Test.class, new TestSerializer());
        registerModule(module);
        configure(SerializationFeature.INDENT_OUTPUT, false);
    }
}

And as you can see, the main culprit is on class TestSerializer

package com.edw.test.jackson;

import com.edw.test.jackson.bean.Test;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import java.io.IOException;

public class TestSerializer extends JsonSerializer<Test> {

    @Override
    public void serialize(Test t, JsonGenerator jgen, SerializerProvider sp) throws IOException, JsonProcessingException {
        jgen.writeStartObject();
        jgen.writeRaw("{");
        jgen.writeFieldName("test01");
        jgen.writeRaw(t.getTest01());
        jgen.writeFieldName("test02");
        jgen.writeRaw(t.getTest02());
        jgen.writeRaw("}");
        jgen.writeEndObject();
    }
}

replacing writeFieldName method with writeRaw method solve my problem.

package com.edw.test.jackson;

import com.edw.test.jackson.bean.Test;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import java.io.IOException;

public class TestSerializer extends JsonSerializer<Test> {
    @Override
    public void serialize(Test t, JsonGenerator jgen, SerializerProvider sp) throws IOException, JsonProcessingException {
        jgen.writeStartObject();
        jgen.writeRaw("test01");
        jgen.writeRaw(t.getTest01());
        jgen.writeRaw("test02");
        jgen.writeRaw(t.getTest02());
        jgen.writeEndObject();
    }
}

Hope it helps :)

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[Java] Cara Cache Data Hasil Query dengan SpringMVC

Pada tulisan kali ini, saya coba membuat suatu metode caching untuk menyimpan data-data master kedalam memory, sehingga tidak perlu query ke database lagi. Hal ini cocok digunakan untuk menyimpan data-data master yang sangat jarang berubah, seperti kode provinsi ataupun kode cabang.

Okay, di tutorial ini saya menggunakan Spring MVC 4, Hibernate dan ehCache sebagai cache provider. Berikut adalah pom.xml yang digunakan,

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.edw</groupId>
    <artifactId>mavenproject5</artifactId>
    <version>1</version>
    <packaging>war</packaging>

    <name>mavenproject5</name>

    <properties>
        <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    
    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>6.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        
        
        <!-- Spring 4 dependencies -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>4.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>4.1.2.RELEASE</version>
         </dependency>
         
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        
        
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.2.2</version>
        </dependency>
        
        <!--ehcache-->
        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
            <version>2.7.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.5</version>
        </dependency>
        
        <!--hibernate-->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>4.3.8.Final</version>
        </dependency>
        
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                    <compilerArguments>
                        <endorseddirs>${endorsed.dir}</endorseddirs>
                    </compilerArguments>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.3</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.6</version>
                <executions>
                    <execution>
                        <phase>validate</phase>
                        <goals>
                            <goal>copy</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${endorsed.dir}</outputDirectory>
                            <silent>true</silent>
                            <artifactItems>
                                <artifactItem>
                                    <groupId>javax</groupId>
                                    <artifactId>javaee-endorsed-api</artifactId>
                                    <version>7.0</version>
                                    <type>jar</type>
                                </artifactItem>
                            </artifactItems>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

Kemudian konfigurasi standard yang digunakan di SpringMVC, applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:cache="http://www.springframework.org/schema/cache"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
        http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd">

    <context:annotation-config/>
    
    <tx:annotation-driven/>
    
    <cache:annotation-driven />
    
    <context:component-scan base-package="com.edw.mavenproject5.service"/>
    
     <!-- datasource  -->
    <bean id="ds" class="org.apache.tomcat.jdbc.pool.DataSource" destroy-method="close"
          p:driverClassName="com.mysql.jdbc.Driver" p:url="jdbc:mysql://localhost/test"
          p:username="root" p:password=""
          p:initialSize="10"
          p:maxActive="50"
          p:maxIdle="10"
          p:minIdle="3"
          p:maxWait="30000"
          p:removeAbandoned="true"
          p:removeAbandonedTimeout="30"
          p:validationQuery="SELECT 1" />
    
    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"
        p:dataSource-ref="ds" p:configLocations="classpath:hibernate.cfg.xml" depends-on="ds">
        <property name="hibernateProperties">
            <value>
                hibernate.dialect=org.hibernate.dialect.MySQLDialect
                hibernate.query.substitutions=true
                hibernate.show_sql=true
                hibernate.enable_lazy_load_no_trans=true
            </value>
        </property>
    </bean> 
    
    <bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>
    
    <bean id="cacheManager" 
          class="org.springframework.cache.ehcache.EhCacheCacheManager" 
          p:cache-manager-ref="ehcache"/>
    <bean id="ehcache" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean"
          p:config-location="classpath:ehcache.xml"/>
    
</beans>

dan dispatcher-servlet.xml,

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">


    <context:component-scan base-package="com.edw.mavenproject5.controller" />
	
    <mvc:annotation-driven />
    <mvc:default-servlet-handler />

    <bean id="viewResolver"
          class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          p:prefix="/WEB-INF/jsp/"
          p:suffix=".jsp" />
</beans>

yang kemudian dipanggil dari web.xml,

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

Nah, ada satu konfigurasi xml yang penting dalam membuat cache. Yaitu ehcache.xml, disana disimpan nama cache serta lama waktu hidupnya

<?xml version="1.0" encoding="UTF-8"?>
<!--
    caching configuration
-->
<ehcache>
    
    <defaultCache
        maxElementsInMemory="5000"
        eternal="true"
        overflowToDisk="false"
        memoryStoreEvictionPolicy="LRU"
    />
    
    <!--2menit-->
    <cache name="duaMenit"
           maxElementsInMemory="10000"
           timeToLiveSeconds="120"
           memoryStoreEvictionPolicy="LRU" 
    />
    
    <!--1menit-->
    <cache name="satuMenit"
           maxElementsInMemory="10000"
           timeToLiveSeconds="60"
           memoryStoreEvictionPolicy="LRU" 
    />
</ehcache>

Nah sekarang kita buat class java-nya, dimulai dari service layer. Perhatikan annotation Cacheable, konfigurasi tersebut adalah konfigurasi yang menandakan lokasi method yang kita cache.

package com.edw.mavenproject5.service;

import com.edw.mavenproject5.bean.Dosen;
import java.util.List;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
@Transactional
public class DosenService {

    @Autowired
    private SessionFactory sessionFactory;
    
    @Cacheable(key = "#root.methodName", value = "duaMenit")
    public List<Dosen> getDosens() {
        return sessionFactory.getCurrentSession().createCriteria(Dosen.class).list();
    }
    
    @Cacheable(key = "#root.methodName + #idDosen", value = "satuMenit")
    public Dosen getDosen(String idDosen) {
        return (Dosen) sessionFactory.getCurrentSession().get(Dosen.class, idDosen);
    }
    
}

Yang kemudian dipanggil dari controller,

package com.edw.mavenproject5.controller;

import com.edw.mavenproject5.service.DosenService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class IndexController {
    
    @Autowired
    private DosenService dosenService;
    
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String index(ModelMap modelMap){
        modelMap.put("dosens", dosenService.getDosens());
        return "index";
    }
    
    @RequestMapping(value = "/get", method = RequestMethod.GET)
    public String get(ModelMap modelMap, String id){
        modelMap.put("dosen", dosenService.getDosen(id));
        return "index";
    }
}

Dan berikut adalah ui yang digunakan untuk menampilkan hasil query didatabase,

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1>Hello World!</h1>
        
        <c:if test="${not empty dosens}">
        <table class="table table-hover table-striped">
            <thead>
                <tr>
                    <th>ID Dosen</th>
                    <th>Nama Dosen</th>
                </tr>
            </thead>
            <tbody>
            <c:forEach items="${dosens}" var="dosen">
                <tr>
                    <td>${dosen.iddosen}</td>
                    <td>${dosen.namadosen}</td>
                </tr>
            </c:forEach>
            </tbody>
        </table>
        </c:if>
        
        <c:if test="${not empty dosen}">
            <h1>Hello Dosen ${dosen.namadosen}!</h1>
        </c:if>
    </body>
</html>

Hasil akhirnya adalah sebagai berikut, data dengan kode 02 dan 321 sudah diubah secara langsung didatabase, namun walaupun browser di-refresh berulang kali, tetap menampilkan data yang lama, yaitu “Dodol” dan “Testing 123 123″.
capture1

Untuk sourcecode lengkapnya bisa diunduh di github, https://github.com/edwinkun/CachingWithSpringMVC. (*)

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Using Sitemesh and Got Error 330 (net::ERR_CONTENT_DECODING_FAILED) on Google Chrome

Basically i never had this error before, it become so challenging because it happen after i adding sitemesh library on my maven project. My first guess is, somehow Sitemesh have a conflicting configuration with other libraries. But i never found any reference nor article to support my theory. Even after i heavily removed several library, the error still happens.

Suddenly i have an enlightenment, after i remove my ehcache gzip compression filter. It turns out that in order to work i need to put sitemesh filter location after ehcache gzip filter.

Here is my final web.xml looks like,

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    
    <!-- gzip -->
    <filter>
        <filter-name>CompressionFilter</filter-name>
        <filter-class>net.sf.ehcache.constructs.web.filter.GzipFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>CompressionFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
    <!-- sitemesh -->
    <filter>
        <filter-name>sitemesh</filter-name>
        <filter-class>com.opensymphony.sitemesh.webapp.SiteMeshFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>sitemesh</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
</web-app>
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SSLHandshakeException When Connecting to Let’s Encrypt CA SSL

Found this weird error when connecting to a HTTPS website, using apache commons httpclient.

javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed
sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Very weird because i can connect to almost every other HTTPS website, but only one website causing this exception. After googling for a while, i found a very interesting solution from MKYong, that is to register the website’s certificate on my JVM.


http://www.mkyong.com/webservices/jax-ws/suncertpathbuilderexception-unable-to-find-valid-certification-path-to-requested-target/

Run this command to generate a new jssecacerts file,

c:\>java InstallCert localhost:443

The only difference is the location where i downloaded InstallCert.java, i downloaded it from this link.


https://github.com/OopsMouse/java-use-examples/blob/master/src/com/aw/ad/util/InstallCert.java

And i also removed the file’s package name, to make it easier to run.

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Exception when Using Spring MVC 4 : No converter found for return value of type: class java.util.ArrayList

I had this exception when moving from Spring MVC 3 to SPring MVC 4, and trying to use @RestController. Here is the complete stacktrace,

 java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList
	at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:158)
	at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:133)
	at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:165)
	at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:80)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:126)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:806)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:729)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)

The solution is actually quite simple, just adding some library on pom.xml seems solve this probem,

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.8.1</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.8.1</version>
        </dependency>
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