This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 8 years ago.
Crashlytics is showing a few crashes on the following line:
if(appObj.getStationsList().get(tag)!=null){
getStationsList() returns a LinkedHashMap<String, StationInfo>. How can I avoid getting this error? It's ironic that my very check to avoid this error actually resulted in it.
You will have to check:
if(appObj.getStationsList()==null)
replace
if(appObj.getStationsList().get(tag)!=null){
with
if(appObj.getStationsList() !=null && appObj.getStationsList().get(tag)!=null){
}
Related
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 2 years ago.
When i am opening my Arduino IDE on my Raspberry PI 4, its getting JAVA Error:
Exception in thread "main" java.lang.NullPointerException
at processing.app.I18n._(I18n.java:51)
at processing.app.Preferences.init(Preferences.java:210)
at processing.app.Base.main(Base.java:117)
Not sure why this is happening.
Please help me to solve this problem.
i advise you to use optional to avoid NPE
https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html
optional<Integer> optional
= Optional.ofNullable(9455);
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 3 years ago.
ret_idx might be null for a new user since its entry in database is not made. So whenever the app detects ret_idx is null, it shows the java.lang.NullPointerException. How do I avoid this exception from crashing my app, considering ret_idx might go null in several cases.
String ret_idx=dataSnapshot.child("name").getValue().toString();
Check whether your input data is null or not and if not then assign it to ret_idx.
if(dataSnapshot.child("name").getValue() != null){
String ret_idx=dataSnapshot.child("name").getValue().toString();
}
This question already has answers here:
how to check for an empty array java [duplicate]
(6 answers)
Closed 4 years ago.
In JasperReport I want to print a field when it does not contain empty array.
How can I check it?
In "Print when expression" it is possible to write:
$F{myField} != null
but as $F{myField} is an empty array (so it is not null) it does not work.
Is there any method to check it? It seems to me that there is no isEmpty() function for JasperReport.
Try write something like:
$F{myField}.length() == 0
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 6 years ago.
What is the problem in my code?
orderIsbnDetails.setIsbn(request.getParameter("isbn"+ i).trim());
This line throws NullpointerException
request.getParameter("isbn"+ i)is null.
null.trim() causes NullPointerException.
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 8 years ago.
I want to print a box into the Java console using Unicode characters, but for some reason it gives me this runtime error:
--------------------Configuration: PacManGame - JDK version 1.7.0_25 <Default> - <Default>--------------------
Exception in thread "main" java.lang.NullPointerException
at Scoreboard.genTopLine(Scoreboard.java:35)
at Scoreboard.<init>(Scoreboard.java:17)
at PacManGame.main(PacManGame.java:36)
Process interrupted by user.
code: http://pastebin.com/nuAsH857
Does anyone know what's wrong?
topline is actually NOT null - it's perfectly fine.
The problem is the use of System.console() which returns null (and hence you get NPE on .writer()).
Use System.out.println() instead and it'll work just fine.
An explanation as to why System.console() doesn't work in your IDE can be found here