How to Solve this java.lang.NullPointerException Error in Java?

Question

I dont know why i am getting the null pointer error .

java.lang.NullPointerException at web.index.getMessage(index.java:30) 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:566) at javax.el.ELUtil.invokeMethod(ELUtil.java:227) at javax.el.BeanELResolver.invoke(BeanELResolver.java:440) at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:198) at com.sun.el.parser.AstValue.getValue(AstValue.java:110) at com.sun.el.parser.AstValue.getValue(AstValue.java:177) at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:183) at org.jboss.weld.module.web.el.WeldValueExpression.getValue(WeldValueExpression.java:50) at com.sun.faces.facelets.el.ELText$ELTextVariable.writeText(ELText.java:216) at com.sun.faces.facelets.el.ELText$ELTextComposite.writeText(ELText.java:123) at com.sun.faces.facelets.compiler.TextInstruction.write(TextInstruction.java:44) at com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:41) at com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:169) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1650) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1650) at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:468) at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:170) at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:132) at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:102) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:76) at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:199) at javax.faces.webapp.FacesServlet.executeLifecyle(FacesServlet.java:708) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:451) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1628) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:258) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:755) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:575) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:159) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:371) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:238) at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:520) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:217) at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:182) at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:156) at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:218) at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:95) at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:260) at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:177) at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:109) at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:88) at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:53) at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:524) at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:89) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:94) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:33) at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:114) at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:569) at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:549) at java.base/java.lang.Thread.run(Thread.java:834)
package web;

    import ejb.EmployeeFacadeLocal;
    import entities.Employee;
    import javax.inject.Named;
    import javax.enterprise.context.SessionScoped;
    import java.io.Serializable;
    import javax.ejb.EJB;
    
    @Named(value = "index")
    @SessionScoped
    public class index implements Serializable {
    
    @EJB
    EmployeeFacadeLocal employee;
    public index() {
        } 
        public String getMessage(){
            Employee emp = new Employee(Integer.SIZE,"XYZ");
            System.out.print(emp) */ Printing Objects */
            employee.create(emp);
            return "Hello All";
        }
    }

package ejb;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

public class EmployeeFacade {

    @PersistenceContext(unitName = "TODO-5PU")
    private EntityManager em;

    @override
    protected EntityManager getEntityManager() {
        return em;
    }
    
}

package ejb;

import java.util.List;
import javax.persistence.EntityManager;


public abstract class AbstractFacade<T> {

    private Class<T> entityClass;

    public AbstractFacade(Class<T> entityClass) {
        this.entityClass = entityClass;
    }

    protected abstract EntityManager getEntityManager();

    public void create(T entity) {
        System.out.print(entity);
        getEntityManager().persist(entity);
    }
}


package ejb;
    
    import entities.Employee;
    import java.util.List;
    import javax.ejb.Local;**strong text**
    @Local
    public interface EmployeeFacadeLocal {
    
        void create(Employee employee);
    }

package entities;

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;

@Entity
@Table(name = "employee")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Employee.findAll", query = "SELECT e FROM Employee e"),
    @NamedQuery(name = "Employee.findById", query = "SELECT e FROM Employee e WHERE e.id = :id"),
    @NamedQuery(name = "Employee.findByName", query = "SELECT e FROM Employee e WHERE e.name = :name")})
public class Employee implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "ID")
    private Integer id;
    @Size(max = 255)
    @Column(name = "NAME")
    private String name;

    public Employee() {
    }

    public Employee(Integer id , String name) {
        this.id = id;
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Employee)) {
            return false;
        }
        Employee other = (Employee) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "entities.Employee[ id=" + id + "]";
    }
    
}

What does netbeans have to do with a nullpointer exception? – B001ᛦ Jul 21 '20 at 19:47 — B001ᛦ, Jul 21 '20 at 19:47
We might be able to help you more if you posted your code. – Charlie Armstrong Jul 21 '20 at 19:49 — Charlie Armstrong, Jul 21 '20 at 19:49

score 2 · Answer 1 · answered Jul 21 '20 at 19:47

2

The "getMessage" at line 30 receives a "null" value. Check from where that values comes and you should be able to pinpoint your problem.

answered Jul 21 '20 at 19:47

Jon

53
1
9

i know that . when i am trying to print an object it is printing the object but , i am not able to insert the data to the database – Vinay Kashyap Jul 21 '20 at 23:26
I suppose the problem is with the "Integer" value rather than with the "String". I can't seem to think of a reason though. Have you tried running in debug mode to see where it crashes? – Jon Jul 22 '20 at 11:52
Yes I tired , to run in debug mode but it crashes at the line em.create(emp) after this it shows the error – Vinay Kashyap Jul 22 '20 at 13:15

How to Solve this java.lang.NullPointerException Error in Java?

1 Answers1