java.lang.NullPointerException while invoke Session Bean [message #439730] |
Tue, 19 January 2010 05:02 |
ying
Messages: 143 Registered: May 2002
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Senior Member |
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Hi,
New to EJB, wish to learn and trying to play around the coding base on the tutorial-> http://technology.amis.nl/blog/4260/ejb-dependency-injection-of-session-bean-facade-in-jsf-12-on-weblogic-103-jsf-with-jpa
This tutorial to me is the most simple to understand. But the tutorial not work for me. I have been googling for about two weeks and did a lot of trial base on example given, but none of them solve my problem
The first error found was in the QuestionController
Integer trck = sbean.save(question); //Error found for this "cannot assign value of type void to variable of type java.lang.integer..
The second error found was there has no "lookup". I have tried to add the lookup for invoking the session bean, as below:
try {
final Context context = new InitialContext();
QuestionSessionLocal =
(QuestionSessionLocal)context.lookup("java:comp/env/ejb/local/QuestionSession");//find this from the web.xml ejb-ref
} catch (Exception ex) {
//TODO : bubble up exception or put in log file.
ex.printStackTrace();
}
public void create() {
try {
final Context context = new InitialContext();
QuestionSessionLocal ques = (QuestionSessionLocal)context.lookup("java:comp/env/ejb/local/QuestionSession");//find this from the web.xml ejb-ref
//ques.hello();
// ques.printHello("Michelle");
ques.save(question);
//return "created";
} catch (Exception ex) {
//TODO : bubble up exception or put in log file.
ex.printStackTrace();
}
}
No error for this, but there has no data save into database after submitting
public String create() {
try {
quesbean.save(question);
addSuccessMessage("Your question was successfully submitted.");
} catch (Exception ex) {
addErrorMessage(ex.getLocalizedMessage());
} return "created";
}
No error for this, but there has no data save into database after submitting and error message also didn't get display
public String create() {
try {
final Context context = new InitialContext();
QuestionSessionLocal quesbean = (QuestionSessionLocal)context.lookup("java:comp/env/ejb/local/QuestionSession");//find this from the web.xml ejb-ref
//Integer trck = quesbean.save(question);
quesbean.save(question);
addSuccessMessage("Your question was successfully submitted.");
} catch (Exception ex) {
addErrorMessage(ex.getLocalizedMessage()); }
return "created"; }
public String createPrint() {
try {
final Context context = new InitialContext();
QuestionSessionLocal quesbean = (QuestionSessionLocal)context.lookup("java:comp/env/ejb/local/QuestionSession");//find this from the web.xml ejb-ref
// Integer trck;
// trck = quesbean.save(question);
//quesbean.save(question);
quesbean.printHello("Michelle");
//addSuccessMessage("Your question was successfully submitted.");
addSuccessMessage("Your question was successfully submitted.");
} catch (Exception ex) {
addErrorMessage(ex.getLocalizedMessage()); }
return "created"; }
Error injecting reference; nested exception is: java.lang.InstantiationException: Error injecting reference
If remove the try and catch, there is -> java.lang.NullPointerException error
Please advise.
Ying.
[Updated on: Tue, 19 January 2010 05:05] Report message to a moderator
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