JPA does not return any data from CloudSQL - maven

Question

I have project based on maven for deployment on GoogleAppEngine. I have local MySQL DB (for development) and remote CloudSQL DB (for production)
My code is based on google github
Data inside CloudSQL and MySQL are identical. I have a problem when trying to retrieve data via named query on production - list of size 0 is returned. On local MySQL DB code returns data correctly. I even tried to retrieve data from ClodSQL using standard java.sql.Connection and I was able to retrieve data. No data are returned only when requested from JPA.
Named query used:
#NamedQueries({(name = "Device.getDevices", = "SELECT d FROM Device d")
my persistence.xml
<?xml version="1.0" encoding="UTF-8" ?>
<persistence
xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
<persistence-unit name="transactions-optional-device">
<class>commander.apprecorder.database.pojos.device.Device</class>
<properties>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="datanucleus.autoCreateSchema" value="true"/>
</properties>
</persistence-unit>
</persistence>
Content of pom.xml
<?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>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<groupId>group</groupId>
<artifactId>art</artifactId>
<properties>
<app.id>appid</app.id>
<app.version>version</app.version>
<appengine.version>1.9.30</appengine.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<gcloud.plugin.version>2.0.9.74.v20150814</gcloud.plugin.version>
<objectify.version>5.1.5</objectify.version>
<guava.version>18.0</guava.version>
<datanucleus.jpa.version>3.1.1</datanucleus.jpa.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.showDeprecation>true</maven.compiler.showDeprecation>
<cloudsql.device.url>
jdbc:google:mysql://some:instance:name/db?user=xxx
</cloudsql.device.url>
<cloudsql.device.url.dev>jdbc:mysql://localhost/db?user=x</cloudsql.device.url.dev>
<datanucleus-core.version>4.0.0-release</datanucleus-core.version>
<datanucleus-maven-plugin.version>4.0.0-release</datanucleus-maven-plugin.version>
<datanucleus-accessplatform-jpa-rdbms.version>4.0.0-release</datanucleus-accessplatform-jpa-rdbms.version>
<javax.persistence.version>2.1.0</javax.persistence.version>
</properties>
<prerequisites>
<maven>3.1.0</maven>
</prerequisites>
<dependencies>
<!-- Compile/runtime dependencies -->
<dependency>
<groupId>com.google.appengine</groupId>
<artifactId>appengine-api-1.0-sdk</artifactId>
<version>${appengine.version}</version>
</dependency>
<dependency>
<groupId>com.google.appengine.tools</groupId>
<artifactId>appengine-gcs-client</artifactId>
<version>0.5</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20151123</version>
</dependency>
<!--JPA start -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.25</version>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-accessplatform-jpa-rdbms</artifactId>
<version>${datanucleus-accessplatform-jpa-rdbms.version}</version>
<type>pom</type>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>javax.persistence</artifactId>
<version>${javax.persistence.version}</version>
</dependency>
<!--JPA end -->
<!-- [START Objectify_Dependencies] -->
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>${guava.version}</version>
</dependency>
<dependency>
<groupId>com.googlecode.objectify</groupId>
<artifactId>objectify</artifactId>
<version>${objectify.version}</version>
</dependency>
<!-- [END Objectify_Dependencies] -->
<!-- Test Dependencies -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-all</artifactId>
<version>2.0.2-beta</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.appengine</groupId>
<artifactId>appengine-testing</artifactId>
<version>${appengine.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.appengine</groupId>
<artifactId>appengine-api-stubs</artifactId>
<version>${appengine.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<!-- for hot reload of the web application-->
<outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>versions-maven-plugin</artifactId>
<version>2.1</version>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>display-dependency-updates</goal>
<goal>display-plugin-updates</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<version>3.2</version>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
<dependencies>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-core</artifactId>
<version>${datanucleus-core.version}</version>
<scope>compile</scope>
</dependency>
</dependencies>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.6</version>
<configuration>
<archiveClasses>true</archiveClasses>
<webResources>
<!-- in order to interpolate version from pom into appengine-web.xml -->
<resource>
<directory>${basedir}/src/main/webapp/WEB-INF</directory>
<filtering>true</filtering>
<targetPath>WEB-INF</targetPath>
</resource>
</webResources>
</configuration>
</plugin>
<plugin>
<groupId>com.google.appengine</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>${appengine.version}</version>
<configuration>
<enableJarClasses>false</enableJarClasses>
<version>${app.version}</version>
<!-- Comment in the below snippet to bind to all IPs instead of just localhost -->
<!-- address>0.0.0.0</address>
<port>8080</port -->
<!-- Comment in the below snippet to enable local debugging with a remote debugger
like those included with Eclipse or IntelliJ -->
<!-- jvmFlags>
<jvmFlag>-agentlib:jdwp=transport=dt_socket,address=8000,server=y,suspend=n</jvmFlag>
</jvmFlags -->
</configuration>
</plugin>
<plugin>
<groupId>com.google.appengine</groupId>
<artifactId>gcloud-maven-plugin</artifactId>
<version>${gcloud.plugin.version}</version>
<configuration>
<set_default>true</set_default>
</configuration>
</plugin>
<!--DB start-->
<plugin>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-maven-plugin</artifactId>
<version>${datanucleus-maven-plugin.version}</version>
<configuration>
<api>JPA</api>
<persistenceUnitName>transactions-optional-device</persistenceUnitName>
<fork>false</fork>
<!--<persistenceUnitName>Demo</persistenceUnitName>-->
<!--<log4jConfiguration>${basedir}/log4j.properties</log4jConfiguration>-->
<verbose>true</verbose>
</configuration>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-core</artifactId>
<version>${datanucleus-core.version}</version>
</dependency>
</dependencies>
</plugin>
<!--JPA end-->
</plugins>
</build>
And servlet for JPA
#Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.setContentType("text/plain");
Map<String, String> properties = new HashMap();
if (SystemProperty.environment.value() == SystemProperty.Environment.Value.Production) {
properties.put("javax.persistence.jdbc.driver", "com.mysql.jdbc.GoogleDriver");
properties.put("javax.persistence.jdbc.url", System.getProperty("cloudsql.device.url"));
} else {
properties.put("javax.persistence.jdbc.driver", "com.mysql.jdbc.Driver");
properties.put("javax.persistence.jdbc.url", System.getProperty("cloudsql.device.url.dev"));
}
// List all the rows.
EntityManagerFactory emf = Persistence.createEntityManagerFactory(
"transactions-optional-device", properties);
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
resp.getWriter().println("performing query");
List<Device> result = em.createNamedQuery("Device.getDevices", Device.class).getResultList();
resp.getWriter().println("Starting to list devices - " + result.size());
for (Device g : result) {
resp.getWriter().println(g.getA() + "_" + g.getB());
}
em.getTransaction().commit();
em.close();
}
There is no error inside app engine log. Can you please tell me what is wrong? Thanks :)

Answer 1

I set log level to ALL and found out that Datanucleus was trying to access datastore. It created new table inside datastore and retrieved its content - no data.
I have no idea why it was trying to access datastore and was not using CloudSQL, but nevermind...
I replaced DataNucles for Hibernate by tutorial inside google github and it worked on first time
Migration was easy, only persistance.xml and pom.xml had to be modified.