Nullpointer exception when instantiating an array

Question

I get a java.lang.NullPointerException when I run the code below:

import org.apache.axis.types.*; //to use UnsignedShort

UnsignedShort a = new UnsignedShort(1);
UnsignedShort b = new UnsignedShort(1);
int c= 123;

VARDATA[] data = new VARDATA[1];

data[0] = new VARDATA();
data[0].setUsType(a);
data[0].setUsIndex(b);
data[0].setUlValue(c);

Please add the stacktrace or the exact location where the exception is thrown from — Bivas
– Bivas, Commented Apr 4, 2011 at 8:05
Please show the full code and not just those lines where you can't find the problem. — Andreas Dolk
– Andreas Dolk, Commented Apr 4, 2011 at 8:10
And add also a little bit more code. For example part of the UnsignedShort or VARDAT class that is throwing the exception. — RoflcoptrException
– RoflcoptrException, Commented Apr 4, 2011 at 8:10

Ben · Accepted Answer · 2011-04-04 08:18:19Z

1

Where do you get the NullPointerException? Which line? Re VARDATA, I don't see it imported, so presume it's part of the same package as the code you're running.

For readability I would prefer to set the first element of data explicitly, and then assign it to the array reference, i.e. something like this:

VARDATA[] data = new VARDATA[1];

VARDATA d = new VARDATA();
d.setUsType(a);
d.setUsIndex(b);
d.setUlValue(c);

data[0] = d;
// And so on ...

… but that's up to you. Either way, I think you need to post VARDATA as I suspect that is where the issue lies here.

edited Apr 4, 2011 at 8:18

answered Apr 4, 2011 at 8:13

Ben

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3 Comments

user690153 Over a year ago

Hello Ben, A slight modification to your code is working perfectly. VARDATA data0 = new VARDATA(); data0.setUsType(varType); data0.setUsIndex(varIndex); data0.setUlValue(varValue); VARDATA[] data = { data0 }; When I define VADATA[] data = new VARDATA[1]; I got error if I assign data[0] = something, the above modified version did the trick. Thanks ... PS: My comments appear in a straight line, how can I format them? This is my first post.

Andreas Dolk Over a year ago

@user690153 - we can't do a formatted multiline comment, but you can format parts of the comment as code - I usually append info like that to my original question.

Ben Over a year ago

@user690153 Glad to hear you got it sorted. Re comments as Andreas_D says, you can only do inline code in comments, using the ` character around the code.

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