Facing a problem with a practice app I’m working on. I’m facing a NullPointerException problem relating to the toString method. Being new to android app development, I’m unsure of the exact cause even after my research into this. Hence I ask for someone who is more familiar with the stack tr…
Tag: nullpointerexception
Hive NVL does not work with Date type of the column – NullpointerException
I am using MapR Hive distribution over HDFS and facing below issue. If for a table the column type is ‘Date’ type, then the NVL function does not work. The same is working for other datatype. It simply throws Even explain function is throwing same exception. Kindly help here. Is it a bug in Hive d…
A utility method representing, “Both not null and not equal” in Java
Comparing this string variable like the following. In case str is null, it will cause a java.lang.NullPointerException to be thrown as obvious. To avoid that, an additional null check may be enforced. Such as, I find it plain ugly. Better could be rewritten as follows. This will never throw a java.lang.NullPo…
null pointer exception error calling method
I get this null pointer exception error if i call a method. if (farm1.cropStat(row, col) ) here’s the method here’s the initialization pls help 🙁 Answer Whenever you see a pattern that looks like this replace it with the equivalent It is the same thing. As far as the error goes, you need to revers…
Android Null Pointer Exception for onclick listener
The following code is giving me null pointer exception even though I can’t find anything wrong with the code. Tried commenting it out and it seems to be working. But still not able to find out what is wrong with the code? tried my own trouble shooting of commenting out the code and such and right now th…
How to avoid NullPointerExceptions from boxed type arithmetic in Java?
Given the following: The requirement for my use case is that result should be null whenever either operand is null (and the same applies for other operators). I know I can use an if statement to do this but is there a smarter way? Answer The best way is not to use Boxed types for normal arithmetic operations.…
Why is my Spring @Autowired field null?
Note: This is intended to be a canonical answer for a common problem. I have a Spring @Service class (MileageFeeCalculator) that has an @Autowired field (rateService), but the field is null when I try to use it. The logs show that both the MileageFeeCalculator bean and the MileageRateService bean are being cr…
Can’t find @Nullable inside javax.annotation.*
I want use @Nullable annotation to eliminate NullPointerExceptions. I found some tutorials on the net, I noticed that this annotation comes from the package javax.annotation.Nullable; but when I import it a compilation error is generated: cannot find symbol Answer You need to include a jar that this class exi…
What are good light-weight design patterns for avoid nulls in Java?
Obviously one of the greatest banes of Java programming is nulls and null-pointer exception. What design patterns are there that don’t add too much to your code but reduce the problem of sand null-pointer exceptions? Answer Null Object pattern. Look at Optional class from google-guava library. Their wik…
Why does my icon handling code throw a NullPointerException?
I have added an image for my button,but when I run that frame this exception will be thrown .why?please help me. line 138: line91: I use this poor checking (Peter Lang recommended)which is:System.out.println(getClass().getResource(“/Images/yahoo_1.gif”)); and it returns null,why? please help me. A…