How do I mock a SessionContext injected via @Resource in Java-EE? -

i'm getting following nullpointerexception:

caused by: java.lang.nullpointerexception @ facadebean.createregistration(facadebean.java:389) 

under facadebean.java:

private sessioncontext context  public createregistrationresponse createregistration() {   try {     // snip   } catch (dataaccessexception de){     context.setrollbackonly(); //---------line 389     throw new serviceexception("error");           } } 

test class

@test(expected = serviceexception.class) public void testcreateregistrationerror() throws serviceexception {     dothrow(dataaccessexception.class).when(mockregistrationperistenceimpl).create(any(registration.class));     facadebeantest.createregistration(registrationfacademock.getcreateregistrationrequest()); } 

could tell me how mock below line, can ignore context.setrollbackonly();

public class facadebean {   public facadebean() {}   @resource   private sessioncontext context } 

easiest way change class use method injection instead of field injection.

in other words, in real class, change this:

@resource private sessioncontext context; 

into this:

private sessioncontext context;  @resource public void setsessioncontext(sessioncontext sessioncontext) {  this.sessioncontext = sessioncontext; } 

then, once you've done that, can inject mock using unit test:

@before public void setup() {   // have other code here   facadebean.setsessioncontext(mock(sessioncontext.class)); } 

you may have issue jaxb if this, though; if happens, read question: sessioncontext injection using @resource annotation

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if can't change code, can access field via reflection, doing this:

@before public void setup() {   field sessioncontextfield = facadebean.class.getdeclaredfield("context");   sessioncontextfield.setaccessible(true);   sessioncontextfield.set(beanobject, mock(sessioncontext.class)); }