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NPE from K&B example SCJP6

 
Nigel Shrin
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Hi, this is an example from K&B SCJP6 page 458.
I'm getting a null pointer exception, but I'm not sure what needs to be changed.
I tried initallising the char array with char[] pw = new char[1000];
but it made no difference. Could someone explain please?



Exception in thread "main" java.lang.NullPointerException
at io_streams.ConsoleReadIn.main(ConsoleReadIn.java:11)


Thank you!
Nigel
 
S Ali
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you must be running this program from eclipse or another IDE.
 
Nigel Shrin
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Yes - I am using Eclipse

Are you able to explain why?

Thanks
 
Ankit Garg
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IDEs like Netbeans and Eclipse don't support the console class right now that's why they return null when you call System.console(). This might be fixed in future versions...
 
Peter Heide
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The Problem is:



This method returns null according to javadoc when the Workbench or Operating System does not give you a console.

I got an exception too using Eclipse and Windows. It worked fine using a MS DOS prompt.

You can at least add to your program to something like this:



I hope someone can find out how we get a valid console within Eclipse.
 
Bert Bates
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As always we strongly recommend that you use the command line to study for the SCJP. All of the questions in the real exam were written in a text file and compiled and run from the command line.

No IDE's were used!
 
Nigel Shrin
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Dear Ankit, Peter & Bert, THANK YOU for taking the time to reply.

Much appreciated.
 
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