Question

i am using guice with java play framework.

i have a simple command interface, and a implementor created in java like this:

public interface ICommand {
public void test();
}

And the implementor

public class CommandImpl implements ICommand {
@Override
public void test() {
System.out.println("test");
}

And then the binding class for @Inject:

public class ICommandModule extends AbstractModule{
@Override
protected void configure() {
bind(ICommand.class).to(CommandImpl.class);
}
}

When i try the command like this:

@Inject
private static ICommand Command;
public static void index() {
Command.test();
render();
}

i get these errors:

From Web Browser:

Execution exception
NullPointerException occured : null

From the Console:

Execution exception (In /app/controllers/Application.java around line 27) NullPointerException occured : null
play.exceptions.JavaExecutionException  
  at play.mvc.ActionInvoker.invoke(ActionInvoker.java:231)  
  at Invocation.HTTP Request(Play!) 
Caused by: 
java.lang.NullPointerException  
  at controllers.Application.index(Application.java:27)     
  at play.mvc.ActionInvoker.invokeWithContinuation(ActionInvoker.java:548)  
  at play.mvc.ActionInvoker.invoke(ActionInvoker.java:502)  
  at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:478)  
  at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:473)  
  at play.mvc.ActionInvoker.invoke(ActionInvoker.java:161)  ... 1 more

Thanks for helping!

Answer 1

You are using static. Inject works only on instance variable and constructors.
You need to use requestStaticInjection in your module.