使用总和时发生空指针异常

Question

While developing an ERP using Spring MVC, JPA/Hibernate i need summing the cr fields of the entity opération but when executing query with createquery

I'm attempting to sum the CR fields of the entity operation in a MVC ERP I'm building but when executing the query with createQuery I get an null pointer exception.

I tested selectQuery without the sum aggregation it worked well. I need clarification.

com.ensi.erp.dao.operationManagerImpl.sommesComptes

`public float sommeComptes(int... doubles) {
        String liste= new String();
        String x;
        for (int d : doubles) {
            x=Integer.toString(d);
            x=x.concat(",");
            liste=liste.concat(x);
        }
    liste=liste.substring(0, liste.length()-1);
    String cc =" select sum(op.cr) from opération op ";
     System.out.println(cc);
        Query req= em.createQuery(cc);
        Number somme=(Number)req.getSingleResult();
        return somme.floatValue();  
    }
    `

com.ensi.entitis.operation

`@Entity
@Table(name="opérations")
public class opération implements Serializable {
@Id 
@Column(name="id")
    private int idop;
@Column(name="journal")
    private char journal;
@Column(name="compte")
    private int compte;
@Column(name="libellé")
    private String libellé;
@Column(name="dateop")
    private Date dateop;
@Column(name="dr")
    private float dr;
@Column(name="cr")
    private float cr;

//getters
public int getIdop(){return idop;}
public char getJournal(){return journal;}
public int getCompte(){return compte;}
public String getLibellé(){return libellé;}
public Date getDateop(){return  dateop;}
public float getDr(){return dr;}
public float getCr(){return cr;}

//setters
public  opération(){};
public  opération(int id,char j,int com,String lib, Date da ,float drr,float crr){idop=id;journal=j;compte=com;libellé=lib;dateop=da;dr=drr;cr=crr;};
public void setIdop(int op){idop=op;}
public void setJournal(char op){journal=op;}
public void setCompte(int op){compte=op;}
public void setLibellé(String op){libellé=op;}
public void setDateop(Date op){dateop=op;}
public void setDr(float op){ dr=op;}
public void setCr(float op){ cr=op;}


}`

com.ensi.metier.construireBilanImpl

package com.ensi.erp.metier;

import org.springframework.transaction.annotation.Transactional;

import com.ensi.erp.dao.OperationManager;
@Transactional
public class construireBilanImpl implements construireBilan {

    private  OperationManager opmanimpl2 ;

    private float immobilisations_corporelles=sommeComptes(1266,1322);
    private float immobilisation_corporelles;
    private float immobilisations_financieres;
    private float actifs_immobilisés;
    private float autres_actifs_nc;
    private float stocks;
    private float clients_et_comptes_rattachés;
    private float autres_actifs_courants;
    private float placements_et_autres;
    private float liquidités_et_equivalents;
    private float Total_actifs_courants;

    private float Capitaux_propres;
    private float Capital_social;
    private float Réserves;
    private float Autres_capitaux_propres;
    private float Résultat_Reporté;
    private float Total_avant_résultat;
    private float résultat_exercice;
    private float Total_capitaux_propres;


    private float Emprunts;
    private float Autres_passifs_financiers;
    private float Provisions;
    private float Total_passifs_nc;

    private float Fournisseurs_et_comptes_rattachés;
    private float Autres_passifs_courants;
    private float Concours_bancaires_et_autres;
    private float passifs_financiers;


    public construireBilanImpl(){};
    public void setOpmanimpl2(OperationManager x){opmanimpl2=x;}

    public float sommeComptes(int... doubles){
        return opmanimpl2.sommeComptes(doubles);


    }

    public float getImmobilisations_corporelles(){return immobilisations_corporelles;}
    public void setImmobilisations_corporelles(float x){immobilisations_corporelles=x;}
}

stackTrace

 INFO : org.springframework.web.context.ContextLoader - Root WebApplicationContext: initialization started
INFO : org.springframework.web.context.support.XmlWebApplicationContext - Refreshing Root WebApplicationContext: startup date [Sun Jun 22 20:55:39 CEST 2014]; root of context hierarchy
INFO : org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loading XML bean definitions from URL [file:/C:/Users/housseminfo/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/ERP_PCD/WEB-INF/classes/root-context.xml]
INFO : org.springframework.context.annotation.ClassPathBeanDefinitionScanner - JSR-250 'javax.annotation.ManagedBean' found and supported for component scanning
INFO : org.springframework.context.annotation.ClassPathBeanDefinitionScanner - JSR-330 'javax.inject.Named' annotation found and supported for component scanning
INFO : org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor - JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
INFO : org.springframework.beans.factory.support.DefaultListableBeanFactory - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@1888c363: defining beans [datasource,persistenceUnitManager,entityManagerFactory,transactionManager,operationmanager,opser,operationmanager2,bilan,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,operationController,homeController,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy
INFO : org.springframework.beans.factory.support.DefaultListableBeanFactory - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@1888c363: defining beans [datasource,persistenceUnitManager,entityManagerFactory,transactionManager,operationmanager,opser,operationmanager2,bilan,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,operationController,homeController,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy
ERROR: org.springframework.web.context.ContextLoader - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'bilan' defined in URL [file:/C:/Users/housseminfo/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/ERP_PCD/WEB-INF/classes/root-context.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ensi.erp.metier.construireBilanImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1011)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:957)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:383)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:283)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4961)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5455)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ensi.erp.metier.construireBilanImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:163)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1004)
    ... 23 more
Caused by: java.lang.NullPointerException
    at com.ensi.erp.metier.construireBilanImpl.sommeComptes(construireBilanImpl.java:48)
    at com.ensi.erp.metier.construireBilanImpl.<init>(construireBilanImpl.java:11)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
    ... 25 more
juin 22, 2014 8:55:40 PM org.apache.catalina.core.StandardContext listenerStart
Grave: Exception lors de l'envoi de l'évènement contexte initialisé (context initialized) à l'instance de classe d'écoute (listener) org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'bilan' defined in URL [file:/C:/Users/housseminfo/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/ERP_PCD/WEB-INF/classes/root-context.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ensi.erp.metier.construireBilanImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1011)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:957)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:383)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:283)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4961)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5455)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.ensi.erp.metier.construireBilanImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:163)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1004)
    ... 23 more
Caused by: java.lang.NullPointerException
    at com.ensi.erp.metier.construireBilanImpl.sommeComptes(construireBilanImpl.java:48)
    at com.ensi.erp.metier.construireBilanImpl.<init>(construireBilanImpl.java:11)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:148)
    ... 25 more

Answer 1

Reading the stack trace, it should be obvious to you. The stack trace tells you exactly where it happens:

java.lang.NullPointerException
at com.ensi.erp.metier.construireBilanImpl.sommeComptes(construireBilanImpl.java:48)
at com.ensi.erp.metier.construireBilanImpl.<init>(construireBilanImpl.java:11)

So the error happens when calling sommeComptes() , which happens when constructing an instance of construireBilanImpl .

Let's look at the code:

private  OperationManager opmanimpl2 ;
// so opmanimpl2 is null.

private float immobilisations_corporelles = sommeComptes(1266,1322)

public float sommeComptes(int... doubles){
    return opmanimpl2.sommeComptes(doubles);
    //       ^-- what's the value of opmanimpl2 again?
}

So, this has absolutely no relation with JPQL queries. Stack traces provide extremely valuable information. Learn to read and understand them.

Side note: please don't use accents in your variable and method names. Stick to ASCII characters. And respect the Java naming conventions. Classes start with an uppercase letter. And don't name doubles what is actually an array of integers.