Juice injector throwing null pointer exception

[ram siddarth]

0

Am trying to learn google juice. I have a InstallConfigurationModule class which has all the dependency needed to create an object of typeA and TypeB .And, got a class say class Car as shown Below and am trying to do constructor injection. When the run method is called am getting null pointer exception at system.out.println line. I know for sure that ModuleA, ModuleB has a reference on creating TypeA, TypeB since in my InstallConfigurationModulemodule, if I say Bind(TypeA.class)or Bind(TypeB.class), I get google juice error, 'A binding to typeA or typeB already configured'.

public class InstallConfigurationModule extends AbstractModule {

@Override
    protected void configure() {
        install(new ModuleA());
        install(new ModuleB());
    }
}
public class Car

{
  private Type A;
  private Type B;

@inject
  void SetCar(Type A, Type B)//not the constructor
 {
   this.A=A;
   this.B=B;
}

private void run()
{
  System.out.println(A.toString()) //throw null pointer exception
}

what Worked:

private void run()
    { 
     Injector injector = Guice.createInjector(new 
                         InstallConfigurationModule());

    TypeA typeA =injector.getInstance(TypeA.class);
      System.out.println(A.toString()) //works fine

    }

Why do I get NPE when I try to do without creatingInjector. Any help appreciated.

PS: very new to juice.

[scl]

How do you run the example where the NPE occurs?

Guice can only inject instances which are created by Guice or are passed to the method injector.injectMembers().

I highly recommend to use constructor injection over field or method injection.
Especially because it makes testing without Guice easier.

[ram siddarth]

Run() is called from an Injected instance, looks like the object isn't null but the ToString() seems to throw null instead of NPE. 

Looking at the stack trace.

Caused by: java.lang.NoSuchMethodException:com.example.car.ToString().

[scl]

Without more code it is almost impossible to help...

What I notice is that you call the method ToString() with a capital T.
In java the method is called toString() with a non capital T.

But this would have been caught by the compiler. So I really start to wonder how this could be...