Question

I tried to inject a Managed Bean to another bean, but failed. That is the first bean:

@ManagedBean(name = "sucBean")
@SessionScoped
public class SucBean implements Serializable {

private static final long serialVersionUID = 1L;

private MapModel advancedModel;

private MapModel advancedModel2;

private Marker marker;

private Suc suc;

private List<Suc> sucDefteri;

private List<Suc> searchResult;

private Suc[] selectedSuc;

private SucService sucService;

private String aramaKriteri;

private String arananKelime;

private SucDataModel sucModel;

    // other getters/setters methods

When I run the web application, I’m getting the

Caused by: java.lang.NullPointerException
at org.primefaces.component.chart.CartesianChart.getCategories(CartesianChart.java:32)
at org.primefaces.component.chart.bar.BarChartRenderer.encodeData(BarChartRenderer.java:121)
at org.primefaces.component.chart.bar.BarChartRenderer.encodeScript(BarChartRenderer.java:51)
at org.primefaces.component.chart.bar.BarChartRenderer.encodeEnd(BarChartRenderer.java:36)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)

The second bean is following:

@ManagedBean(name="chartBean")
@SessionScoped
public class ChartBean implements Serializable {

/**
 * 
 */
private static final long serialVersionUID = 1L;

private CartesianChartModel categoryModel;

@ManagedProperty("#{sucBean}")
private SucBean sucBean;

private int[] sucSayilari=new int[9];


public ChartBean()
{
    createCategoryModel();
}

Answer 1

I think this is the problem:

public ChartBean()
{
    createCategoryModel();
}

Your dependencies are not set at this point because the JSF implementation first instantiates your bean (and that means that the constructor must finish) and then injects its dependencies, so if you are using the injected bean in createCategoryModel() it will be a null reference.

If you need to do something with your bean AFTER dependencies are set use a method anotated with @PostConstruct:

public ChartBean(){
}

@PostConstruct
public void init(){
   createCategoryModel();
}