non-static variable role cannot be referenced from a static context- JDO Querydsl - sql

Question

I am building one maven project using JDO, Querydsl. But in my DaoImpl class one line is showing error which is: "non-static variable role cannot be referenced from a static context"
My pojo classes are:
User.java
#PersistenceCapable(table="User_Login")
public class User {
#PrimaryKey
#Column(name="user_id")
private Integer userId=0;
#Column(name="user_profile_name")
private String userProfileName=null;
#Column(name="user_email")
private String userEmail=null;
#Column(name="user_contact")
private String userContact=null;
#Column(name="user_name")
private String userName=null;
#Column(name="user_password")
private String userPassword=null;
#Column(name="user_role_id")
private Integer userRoleId=0;
private Role userRole=null;
Role.java:
#PersistenceCapable(table="User_Role")
public class Role {
#PrimaryKey
#Column(name="id")
private Integer roleId=0;
#Column(name="role")
private String role=null;
My required result will be:
userid: 1, role: admin
my DAOImpl class:
public List<User> getUser(String user_name, String user_password) {
PersistenceManager pm =
this.persistenceManagerFactory.getPersistenceManager();
Transaction tx = pm.currentTransaction();
SQLTemplates templates = new MySQLTemplates();
QUser user = QUser.user;
QRole role = QRole.role;-----------**this is showing error**
JDOSQLQuery query = new JDOSQLQuery(pm, templates);
try {
// Start the transaction
tx.begin();
List<User> result = query.from(user)
.innerJoin(role).on(user.userRoleId.eq(role.roleId))
.where(user.userName.eq(user_name),
user.userPassword.eq(user_password)).
list(user);
query.close();
tx.commit();
return result;
}
finally {
if (tx.isActive())
{
// Error occurred so rollback the transaction
tx.rollback();
}
pm.close();
}
My pom.xml is:
<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.titas</groupId>
<artifactId>QuerydslJDO</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>QuerydslJDO</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>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>javax.jdo</groupId>
<artifactId>jdo-api</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>com.mysema.querydsl</groupId>
<artifactId>querydsl-apt</artifactId>
<version>3.6.3</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.mysema.querydsl</groupId>
<artifactId>querydsl-jdo</artifactId>
<version>3.6.3</version>
</dependency>
<dependency>
<groupId>com.mysema.querydsl</groupId>
<artifactId>querydsl-sql</artifactId>
<version>3.6.3</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.6.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<compilerArguments>
<endorseddirs>${endorsed.dir}</endorseddirs>
</compilerArguments>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.1.1</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.1</version>
<executions>
<execution>
<phase>validate</phase>
<goals>
<goal>copy</goal>
</goals>
<configuration>
<outputDirectory>${endorsed.dir}
</outputDirectory>
<silent>true</silent>
<artifactItems>
<artifactItem>
<groupId>javax</groupId>
<artifactId>javaee-endorsed-
api</artifactId>
<version>6.0</version>
<type>jar</type>
</artifactItem>
</artifactItems>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.mysema.maven</groupId>
<artifactId>apt-maven-plugin</artifactId>
<version>1.0.4</version>
<executions>
<execution>
<goals>
<goal>process</goal>
</goals>
<configuration>
<outputDirectory>target/generated-sources
/java</outputDirectory>
<processor>com.mysema.query.apt.jdo.
JDOAnnotationProcessor</processor>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.mysema.querydsl</groupId>
<artifactId>querydsl-maven-plugin</artifactId>
<version>2.9.0</version>
<executions>
<execution>
<goals>
<goal>export</goal>
</goals>
</execution>
</executions>
<configuration>
<jdbcDriver>com.mysql.jdbc.Driver</jdbcDriver>
<jdbcUrl>jdbc:mysql://localhost:3306/login</jdbcUrl>
<jdbcUser>root</jdbcUser>
<packageName>com.titas.model</packageName>
<targetFolder>${project.basedir}/target/generated-sources
/java</targetFolder>
</configuration>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
</dependencies>
</plugin>
</plugins>
<resources>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
</build>

Answer 1

Since your Role.java already contains a property 'role' Querydsl cannot generate your standard variable as 'QRole.role', so it is named 'QRole.role1'.