spring Posts

Creating a Simple SpringBoot App and Deploy it on Top of Openshift in Less than Two Minutes

Today im trying to demonstrate how easy and fast to deploy a Spring Boot application on ton of Openshift Platform. But before we go too far, let us familiarize ourself with Openshift. Openshift is a Red Hat product which is a leading hybrid cloud, enterprise Kubernetes application platform. It lets you easily and quickly build, develop, and deploy in nearly any infrastructure, public or private. Whether it’s on-premise, in a public cloud, or hosted.

For this scenario, im trying to deploy a hello world apps which are build using Spring Boot. It only consist of 2 java class, and a configuration file (maven). Below is my main java class.

package com.edw.test.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

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

}

And below is the java class im using for controller,

package com.edw.test.demo;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;

@RestController
public class IndexController {
    @GetMapping("/")
    public HashMap get() {
        return new HashMap(){{
            put("Message", "Hello World");
        }};
    }
}

And my pom.xml file,

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.edw.test</groupId>
    <artifactId>demo</artifactId>
    <version>1.0.1</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

After everything runs well on your local, lets put those code online by using Github. Once published to Github, remember to copy your github’s project url. We shall need it later.

First thing to do after creating your code is creating your free Openshift account, you can login to it with your RedHat Developer account. Next is opening your Openshift web console, and click “create project” button and insert its name,

Click on project and choose “Browse Catalog”,

And chose RedHat Open JDK 8, and create application

And below is perhaps the most important feature, that is inserting your github url on Openshift. So that it can take your code and build it accordingly. And dont forget to checklist “Create Route”.

Once application is successfully created, it will shows logs as shown below and also it will show list of pods and its status,

Next is checking where is our route,

Clicking on it will show to the index page of our SpringBoot app,

Have fun using Openshift (^)

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Error “Overriding bean of same name declared in: class path resource” when Integrating Spring Cloud Sleuth and ActiveMQ Library

Had this weird error when integrating ActiveMQ JMS and Spring Cloud Sleuth,

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.jms.config.DefaultJmsListenerContainerFactory]: Factory method 'jmsListenerContainerFactory'
threw exception; nested exception is java.lang.IllegalStateException: @Bean method JMSReceiver.receiverActiveMQConnectionFactory called as bean reference for type [org.apache.activemq.ActiveMQConnectionFactory] but overridden by non-compatible bean instance of type [org.springframework.cloud.sleuth.instrument.messaging.LazyConnectionFactory].
Overriding bean of same name declared in: class path resource [id/co/edw/xxx/api/notificationengineservice/jmsClient/JMSReceiver.class]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:622)
    ... 27 common frames omitted
Caused by: java.lang.IllegalStateException: @Bean method JMSReceiver.receiverActiveMQConnectionFactory called as bean reference for type [org.apache.activemq.ActiveMQConnectionFactory]
but overridden by non-compatible bean instance of type [org.springframework.cloud.sleuth.instrument.messaging.LazyConnectionFactory]. Overriding bean of same name declared in:
class path resource [id/co/edw/xxx/api/notificationengineservice/jmsClient/JMSReceiver.class]
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.resolveBeanReference(ConfigurationClassEnhancer.java:418)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:366)
    at id.co.edw.xxx.api.notificationengineservice.jmsClient.JMSReceiver$$EnhancerBySpringCGLIB$$10f22401.receiverActiveMQConnectionFactory(<generated>)
    at id.co.edw.xxx.api.notificationengineservice.jmsClient.JMSReceiver.jmsListenerContainerFactory(JMSReceiver.java:40)
    at id.co.edw.xxx.api.notificationengineservice.jmsClient.JMSReceiver$$EnhancerBySpringCGLIB$$10f22401.CGLIB$jmsListenerContainerFactory$1(<generated>)
    at id.co.edw.xxx.api.notificationengineservice.jmsClient.JMSReceiver$$EnhancerBySpringCGLIB$$10f22401$$FastClassBySpringCGLIB$$36560b20.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363)
    at id.co.edw.xxx.api.notificationengineservice.jmsClient.JMSReceiver$$EnhancerBySpringCGLIB$$10f22401.jmsListenerContainerFactory(<generated>)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:567)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    ... 28 common frames omitted

It happens because Spring Sleuth overriding bean provided by JMSReceiver,

package id.co.edw.xxx.api.notificationengineservice.jmsClient;
 
 
import org.apache.activemq.ActiveMQConnectionFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jms.annotation.EnableJms;
import org.springframework.jms.config.DefaultJmsListenerContainerFactory;
 
import java.util.ArrayList;
import java.util.Arrays;
 
@Configuration
@EnableJms
public class JMSReceiver {
 
 
    @Value("somevalue")
    private String brokerUrl;
 
    @Bean
    @Primary
    public ActiveMQConnectionFactory receiverActiveMQConnectionFactory() {
        ActiveMQConnectionFactory activeMQConnectionFactory =
                new ActiveMQConnectionFactory();
        activeMQConnectionFactory.setBrokerURL(brokerUrl);
        activeMQConnectionFactory.setTrustedPackages(new ArrayList<>(Arrays.asList("id.co.edw.xxx.api,java.lang".split(","))));
 
 
        return activeMQConnectionFactory;
    }
 
    @Bean
    public DefaultJmsListenerContainerFactory jmsListenerContainerFactory() {
        DefaultJmsListenerContainerFactory factory =
                new DefaultJmsListenerContainerFactory();
        factory
                .setConnectionFactory(receiverActiveMQConnectionFactory());
        factory.setConcurrency("2");
 
        return factory;
    }
}

Problem solved after remarking Sleuth import on pom.xml,

<dependency>
	<groupId>javax.activation</groupId>
	<artifactId>javax.activation-api</artifactId>
</dependency>


<!--        <dependency>-->
<!--            <groupId>org.springframework.cloud</groupId>-->
<!--            <artifactId>spring-cloud-starter-sleuth</artifactId>-->
<!--            <version>2.1.2.RELEASE</version>-->
<!--        </dependency>-->


<dependency>
	<groupId>com.github.tomakehurst</groupId>
	<artifactId>wiremock-standalone</artifactId>
	<version>2.19.0</version>
	<scope>test</scope>
</dependency>

<!--     swaggwer -->
<dependency>
	<groupId>io.springfox</groupId>
	<artifactId>springfox-swagger2</artifactId>
	<version>2.9.2</version>
</dependency>

<!-- SMTP SPRING -->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-mail</artifactId>
</dependency>

<dependency>
	<groupId>javax.activation</groupId>
	<artifactId>javax.activation-api</artifactId>
</dependency>
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Importing Swagger API Into Postman

There is one feature that i like the most from Postman, is the ability to import apis from Swagger API directly. On this example, im using two most popular Swagger generator, Springfox and swagger-jaxrs. Basically, this is how you do it,

First need to click on button import on the top of Postman,
postman 1

Next is, selecting import from link,
postman 2

And paste your Swagger documentation url on that textbox, url for Springfox is like this “http://(urlname)/v2/api-docs”, and on Swagger-jaxrs is on “http://(urlname)/api/swagger.json”.

:-D

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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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How to Find Root Cause of Error 400 on SpringMVC using Log4J

Error 400 is basically telling us that our request is syntactically incorrect. But it will need a while to found out which parameter is incorrect, especially when you are submitting a lot of parameters.

But do not worry, on SpringMVC we can always log which parameters causing error 400 using Log4J. Adding these values on your log4j.properties will display the error location.

log4j.logger.org.springframework.web=debug

And we can see the root cause on our log file,

2017-02-28 22:33:07,241 [DefaultHandlerExceptionResolver] DEBUG org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver:133 - Resolving exception from handler [public java.util.Map xxx.yyy.controller.ZZZController.saveZZZ(xxx.yyy.bean.DDDD,org.springframework.web.multipart.MultipartFile,org.springframework.web.multipart.MultipartFile,javax.servlet.http.HttpSession)]: org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'DDDD' on field 'rupiah': rejected value [100.000.000,000000]; codes [typeMismatch.DDDD.rupiah,typeMismatch.rupiah,typeMismatch.java.math.BigDecimal,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [DDDD.rupiah,rupiah]; arguments []; default message [rupiah]]; default message [Failed to convert property value of type [java.lang.String] to required type [java.math.BigDecimal] for property 'rupiah'; nested exception is java.lang.NumberFormatException]

As you can see, it happens because i expect a BigDecimal on my bean, but i send a String instead.

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