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I create a class which extends Exception class, I got this warning on Eclipse

The serializable class PhoneAlreadyExists does not declare a static final serialVersionUID field of type long

how to remove it please ?

public class PhoneAlreadyExists extends Exception { public PhoneAlreadyExists() { // TODO Auto-generated constructor stub super(); } PhoneAlreadyExists(String message) { super(message); } }
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  • 5
    Add a serialVersionUID field to the class. Commented Feb 23, 2013 at 21:22
  • 1
    Its just a warning and it won't crash anything. If it really bothers you, you can suppress it by hovering over the warning and clicking the first suggestion (or whichever one says that you can suppress it). Commented Feb 23, 2013 at 21:22
  • Have a look at my answer below. That may help. Commented Apr 4, 2013 at 9:48
  • Also duplicate of this and this and this and this and more. Commented Jan 5, 2018 at 23:15

6 Answers 6

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To change the behavior in eclipse globally: Go to Preferences->Java->Compiler->Errors/Warnings->Potential Programming Problems. There's an entry for this specific problem. You can change it for a specific project too.

That answers your question, although - I'd recommend to leave it at warning level and add the missing fields. Or add the SuppressWarnings annotation to those serializable classes that really do not need the field because they'll never be serialized.

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7 Comments

Thanks. Actually it's Preferences -> Java -> Compiler -> Errors/warnings -> Potential programming problems
Thanks for the correction! I've updated my answer with the correct path.
Funny how the most useful/to the point answers are always left behind, yours should be the accepted answer.
Note that you get this warning when deriving an anonymous type from some serializable type - even if the supertype has its own @SuppressWarnings("serial")!!). E.g., when using Guava's TypeToken. (Eclipse 4.4.2.) I suppose I could annotate the site of the new anonymous type ... but it's a PITA and I'd rather turn this nearly useless warning off altogether.
@Anony-Mousse Generally I agree with you, but unless you are serializing your exceptions, sending them over RMI/CORBA or storing them to disk, most people will not encounter problems with exception serialization in most domains. If you are in a domain where you will be affected, you (should) know. The 99% will not see issues in their web apps due to this. That's why it should be possible to globally disable this for a project. Too bad there is no globally available fix like .eslintrc for Java.
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Add an annotation @SuppressWarnings("serial") on your class, to ignore that warning

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10 Comments

Or just resolve the warning correctly. It's usually better than ignoring it, even if it is 4 lines of code (including JavaDoc, of course - otherwise it's just 1)
Of course, but usually we needn't to define serial version, therefore this is quick solution for the problem.
It's not really quicker. Java IDEs can generate serial version fields using the "quick fix" function. E.g. eclipse.
@Anony-Mousse every line of code represents intent. If you do not intend the object to be serialized, and you add code to support contrary, you are writing incoherent code. If we adhere to all possible "3 lines of code" changes, the intentional part of your code will end up being minority of your actual code, which is dangerous if you want to write code that you want to be able to come back to later. It is compiler's, and fragile base class, and typeclass's responsibility to take care of spicing up your classes, not your specific class itself.
@Dmitry If you don't intend the class to be serializable, then don't implement the Serializable interface! It's not the serialVersionUID field that causes the inconsistency, nor will ignoring the problem solve it. All this field does is help recognize deserialization issues when a class definition changes. Adding it will not "enable" serialization, and ignoring the warning will not prevent serialization.
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You need to declare a static final serialVersionUID field of type long.

Look up the Serializable API of Java. Exceptions must implement Serializable, and Serializable classes must have a serialVersionUID:

public static final long serialVersionUID = 1L;

Whenever you make incompatible changes to the class, increment this version.

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2

To ignore the warning "The serializable class ClASSNAME does not declare a static final serialVersionUID......" do the following inside eclipse*:

  1. Click Window-Preferences-Java-Compiler-Errors/Warnings
  2. Click on "Potential Programming Problems"
  3. Scroll down to "Serializable class without serialVersionUID"
  4. Choose "Ignore"
  5. Click Apply
  6. Click OK

Save and close your eclipse IDE When you reopen eclipse, these specific warnings should no longer be listed.

*For this example solution I'm using Eclipse IDE for Java Developers - Version: Mars.2 Release (4.5.2)

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1

just add this code @SuppressWarnings("serial") above your public class PhoneAlreadyExists extends Exception { line

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Please provide additional detail and format your answer appropriately.
1

It is best to add the serialversionUID in most cases, but eclipse gives the warning on all swing derived classes, which will never be serialized. I tried changing the setting at preferences->Java -> Compiler -> Errors/warnings -> Potential programming problems, but it had no effect. So I guess the best solution would be to suppress the warning on each class that will never be serialized; or grit your teeth and ignore the warning.

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