IntelliJ IDEA generating serialVersionUID

Question

How do generate this value in IntelliJ IDEA?

I go to Settings -> Errors -> Serialization issues -> Serializable class without ‘serialVersionUID’, but it still doesn't show me the warning. My class PKladrBuilding parent implements interface Serializable.

Part of the code:

public class PKladrBuilding extends PRQObject

public abstract class PRQObject extends PObject

public abstract class PObject implements Serializable

Are you sure you need to generate a value, rather than defining your own? If you are creating a new class, I would recommend you define e.g. `1L` as your ID and increment when your serialized form changes. (See http://stackoverflow.com/questions/888335/why-generate-long-serialversionuid-instead-of-a-simple-1l). — Duncan Jones, Oct 16 '12 at 10:15
http://stackoverflow.com/questions/24573643/how-to-generate-serial-version-uid-in-intellij has a very good solution. — Pankaj Kumar, Dec 27 '16 at 07:06

score 618 · Accepted Answer · edited Oct 05 '18 at 18:48

618

I am not sure if you have an old version of IntelliJ IDEA, but if I go to menu File → Settings... → Inspections → Serialization issues → Serializable class without 'serialVersionUID'` enabled, the class you provide give me warnings.

Enter image description here

If I try the first class I see:

Enter image description here

BTW: It didn't show me a warning until I added { } to the end of each class to fix the compile error.

edited Oct 05 '18 at 18:48

Peter Mortensen

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answered Oct 16 '12 at 10:17

Peter Lawrey

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I am using idea 11.1.3 and I have enabled this option too but it still does not show the warning =( – Oct 16 '12 at 10:17
I assume you have `{ }` like I have? – Peter Lawrey Oct 16 '12 at 10:18
2

Try `File` | `Invalidate Caches`, if it doesn't help, contact support@jetbrains.com with a sample project to reproduce. – CrazyCoder Oct 16 '12 at 10:19
... and try restarting your IDE. – Peter Lawrey Oct 16 '12 at 10:20
I show just part of the code. Those classes fill with a lot of code. I maked Invalidate Caches but it still does not helps. – Oct 16 '12 at 10:29
... and when you restarted your IDE? (btw I have 11.1.3 as well) – Peter Lawrey Oct 16 '12 at 10:35
I have restarted it twice. On your image you Show warning on parental class. Try to `Add 'serialVersionUID'` on PKladrBuilding – Oct 16 '12 at 10:39
Added an example for the first class as well. – Peter Lawrey Oct 16 '12 at 10:48
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Check `idea.log` (Help | Reveal Log in ...) for exceptions, encrypted home directory on Linux is known to cause problems because of the [kernel bug](https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1047261). – CrazyCoder Oct 16 '12 at 10:53
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i have a lot of exceptions there.. like java.lang.NoClassDefFoundError: org/intellij/lang/annotations/MagicConstant; – Oct 16 '12 at 10:58
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Reinstall IDEA from http://www.jetbrains.com/idea/download/index.html and remove all the plug-ins from `~/.IntelliJIdea11/config/plugins`. Verify that IDEA/project folders are not inside encrypted home directory, relocate IDEA folders if your home is encrypted: http://devnet.jetbrains.net/docs/DOC-181. – CrazyCoder Oct 16 '12 at 11:05
I try to keep my plugins to a minimum. You get less unexpected behaviour that way. ;) – Peter Lawrey Oct 16 '12 at 11:06
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I have reinstalled IDEA and removed plug-ins and it helps me. Tnx a lot. – Oct 16 '12 at 12:10
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I am on IDEA 12.1.4, the warning shown up, but there is no "Add 'serialVersionID' field" prompt. – Gelin Luo Sep 14 '13 at 21:15
Worked on AndroidStudio 0.5.8. Thanks! – dum4ll3 May 16 '14 at 17:33
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@green with cursor on the warning try alt-enter – jk. Oct 21 '14 at 11:06
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The way I got it working in the v15 is to hover over the ClassName to see the warning and move my mouse slowly towards the gutter. At that point the "lightbulb" shows up on the screen. (Try this a few times if it does not work as intended the first time). Then you can click on the create field option to create the uid. Hope this helps people who are stuck on this. – Niyaz Jan 14 '16 at 22:11
In v15 (did not test it in previous versions), after you set up the Inspection, you can use the shortcut 'ALT+' **when your courser is on the class name**. This will show you the menu with the option "Add 'serialVersionUID' field" – david00f Mar 05 '16 at 16:48
This auto-fix feature seems to be gone from IntelliJ 2017 Ultimate edition. – Basil Bourque Jan 05 '18 at 22:02
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Nikhil Katre points to the right direction how to enable this in IntelliJ 2017. Unfortunately this does not always seem to work. I had to resort to the plugin in order to make it work consistently. – Stefan Hendriks Feb 06 '18 at 14:58
Why is this not enabled per default? – powder366 May 20 '20 at 13:27

score 181 · Answer 2 · edited Oct 05 '18 at 18:50

181

Install the GenerateSerialVersionUID plugin by Olivier Descout.

Go to: menu File → Settings → Plugins → Browse repositories → GenerateSerialVersionUID

Install the plugin and restart.

Now you can generate the id from menu Code → Generate → serialVersionUID` or the shortcut.

edited Oct 05 '18 at 18:50

Peter Mortensen

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answered Aug 20 '13 at 17:29

Sileria

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Should one require an external plugin really in order to get this working? – H.Rabiee May 30 '14 at 21:34
Yes you need a plugin which is already part of IntelliJ plugin repository. – Sileria Jun 13 '14 at 17:09
Timeout for me on Android Studio – Laurent Russier Sep 24 '15 at 08:15
Works in 2017.3.4 - I noticed you could not generate a serialVersionUID when it was defined in a base class (even though it is private static and should not matter in that sense). This plugin just offered the option and works. Nice. – Stefan Hendriks Feb 06 '18 at 14:57
Answer is correct, but a plugin which breaks every few major version is not as good as using the internal solution also posted here. – Hannes Schneidermayer Sep 17 '18 at 13:37
there;s no need for a plugin to do that. It's already built in in the IDE. – saran3h Aug 24 '21 at 09:28

Nikhil Katre · Answer 3 · 2019-06-05T21:31:28.183

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Without any plugins: You just need to enable highlight in IntelliJ:

IntelliJ Preferences -> Editor -> Inspections -> Java -> Serialization issues -> Serializable class without 'serialVersionUID' - set flag and click 'OK'.

Now, if your class implements Serializable, you will see highlight, and alt+Enter on class name will propose to generate private static final long serialVersionUID.

PS: Taken from here

edited Jun 05 '19 at 21:31

answered Mar 15 '17 at 05:29

Nikhil Katre

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Thanks. I don't know why I don't see the light bulb, but clicking on the class name and typing Alt-Enter does the trick. – John S Sep 10 '18 at 16:51
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Answer is stolen from [here](https://stackoverflow.com/questions/24573643/how-to-generate-serial-version-uid-in-intellij/36007392#36007392) – Serhii Maksymchuk Feb 21 '19 at 10:11
this is more uptodate – Christian Matthew Jun 11 '19 at 18:44

score 41 · Answer 4 · answered Jul 16 '17 at 04:53

After spending some time on Serialization, I find that, we should not generate serialVersionUID with some random value, we should give it a meaningful value.

Here is a details comment on this. I am coping the comment here.

Actually, you should not be "generating" serial version UIDs. It is a dumb "feature" that stems from the general misunderstanding of how that ID is used by Java. You should be giving these IDs meaningful, readable values, e.g. starting with 1L, and incrementing them each time you think the new version of the class should render all previous versions (that might be previously serialized) obsolete. All utilities that generate such IDs basically do what the JVM does when the ID is not defined: they generate the value based on the content of the class file, hence coming up with unreadable meaningless long integers. If you want each and every version of your class to be distinct (in the eyes of the JVM) then you should not even specify the serialVersionUID value isnce the JVM will produce one on the fly, and the value of each version of your class will be unique. The purpose of defining that value explicitly is to tell the serialization mechanism to treat different versions of the class that have the same SVUID as if they are the same, e.g. not to reject the older serialized versions. So, if you define the ID and never change it (and I assume that's what you do since you rely on the auto-generation, and you probably never re-generate your IDs) you are ensuring that all - even absolutely different - versions of your class will be considered the same by the serialization mechanism. Is that what you want? If not, and if you indeed want to have control over how your objects are recognized, you should be using simple values that you yourself can understand and easily update when you decide that the class has changed significantly. Having a 23-digit value does not help at all.

Hope this helps. Good luck.

I actually would re-generate the `serialVersionUID` with a new random number when I don't want to support old versions on deserialization. Maybe I don't need to use random numbers but can start with 1 and increment it. However, `3L` doesn't have more meaning to me then `-3518231192373568183L`. Therefore, I guess both solutions work similarly. The random number might have the advantage that it woks on non-linear histories with forks and branches, though. — JojOatXGME, Jul 05 '19 at 22:49

score 18 · Answer 5 · answered May 06 '20 at 17:46

Easiest modern method: Alt+Enter on

private static final long serialVersionUID = ;

IntelliJ will underline the space after the =. put your cursor on it and hit alt+Enter (Option+Enter on Mac). You'll get a popover that says "Randomly Change serialVersionUID Initializer". Just hit enter, and it'll populate that space with a random long.

score 17 · Answer 6 · answered Mar 18 '15 at 10:01

17

In order to generate the value use

private static final long serialVersionUID = $randomLong$L;
$END$

and provide the randomLong template variable with the following value: groovyScript("new Random().nextLong().abs()")

https://pharsfalvi.wordpress.com/2015/03/18/adding-serialversionuid-in-idea/

answered Mar 18 '15 at 10:01

pharsfalvi

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love this comment, using live templates this is for sure the fastest solution and most customisable (I removed the newline for example). To configure go to Android Studio > Preferences > Editor > Live Templates and create a new one there (plus icon) with this value and use edit variables to enter the script – hcpl Oct 16 '17 at 15:34

score 14 · Answer 7 · edited Sep 14 '17 at 21:48

14

In addition you can add live template that will do the work.

To do it press Ctrl+Alt+S -> "Live Templates" section -> other (or w/e you wish)

And then create a new one with a definition like this:

private static final long serialVersionUID = 1L;
$END$

Then select definition scope and save it as 'serial'

Now you can type serialTAB in class body.

edited Sep 14 '17 at 21:48

acdcjunior

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answered Sep 18 '14 at 11:59

fallens4e

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Alexander · Answer 8 · 2019-12-09T13:03:39.127

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Another way to generate the serialVersionUID is to use >Analyze >Run Inspection by Name from the context menu ( or the keyboard short cut, which is ctrl+alt+shift+i by default) and then type "Serializable class without 'serialVersionUID'" (or simply type "serialVersionUID" and the type ahead function will find it for you.

You will then get a context menu where you can choose where to run the inspections on (e.g. all from a specific module, whole project, one file, ...)

With this approach you don't even have to set the general inspection rules to anything.

edited Dec 09 '19 at 13:03

answered Jun 14 '19 at 07:55

Alexander

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Nice, this did the job for me. It found the missing variable and presented the option to add it. – arenaq Jul 30 '19 at 09:50

score 2 · Answer 9 · edited Oct 18 '18 at 03:12

2

With version v2018.2.1

Go to

Preference > Editor > Inspections > Java > Serialization issues > toggle "Serializable class without 'serialVersionUID'".

A warning should appear next to the class declaration.

edited Oct 18 '18 at 03:12

Quoc Nguyen

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answered Oct 18 '18 at 01:45

0x00A5

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score 1 · Answer 10 · edited Oct 05 '18 at 18:52

If you want to add the absent serialVersionUID for a bunch of files, IntelliJ IDEA may not work very well. I come up some simple script to fulfill this goal with ease:

base_dir=$(pwd)
src_dir=$base_dir/src/main/java
ic_api_cp=$base_dir/target/classes

while read f
do
    clazz=${f//\//.}
    clazz=${clazz/%.java/}
    seruidstr=$(serialver -classpath $ic_api_cp $clazz | cut -d ':' -f 2 | sed -e 's/^\s\+//')
    perl -ni.bak -e "print $_; printf qq{%s\n}, q{    private $seruidstr} if /public class/" $src_dir/$f
done

You save this script, say as add_serialVersionUID.sh in your ~/bin folder. Then you run it in the root directory of your Maven or Gradle project like:

add_serialVersionUID.sh < myJavaToAmend.lst

This .lst includes the list of Java files to add the serialVersionUID in the following format:

com/abc/ic/api/model/domain/item/BizOrderTransDO.java
com/abc/ic/api/model/domain/item/CardPassFeature.java
com/abc/ic/api/model/domain/item/CategoryFeature.java
com/abc/ic/api/model/domain/item/GoodsFeature.java
com/abc/ic/api/model/domain/item/ItemFeature.java
com/abc/ic/api/model/domain/item/ItemPicUrls.java
com/abc/ic/api/model/domain/item/ItemSkuDO.java
com/abc/ic/api/model/domain/serve/ServeCategoryFeature.java
com/abc/ic/api/model/domain/serve/ServeFeature.java
com/abc/ic/api/model/param/depot/DepotItemDTO.java
com/abc/ic/api/model/param/depot/DepotItemQueryDTO.java
com/abc/ic/api/model/param/depot/InDepotDTO.java
com/abc/ic/api/model/param/depot/OutDepotDTO.java

This script uses the JDK serialVer tool. It is ideal for a situation when you want to amend a huge number of classes which had no serialVersionUID set in the first place while maintain the compatibility with the old classes.

score 1 · Answer 11 · answered Jun 27 '16 at 04:10

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I am using Android Studio 2.1 and I have better consistency of getting the lightbulb by clicking on the class Name and hover over it for a second.

answered Jun 27 '16 at 04:10

Johnny Wu

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score 1 · Answer 12 · edited Oct 05 '18 at 18:53

Add a live template called "ser" to the other group, set it to "Applicable in Java: declaration", and untick "Shorten FQ names". Give it a template text of just:

$serial$

Now edit variables and set serial to:

groovyScript("(System.env.JDK_HOME+'/bin/serialver -classpath '+com.intellij.openapi.fileEditor.FileDocumentManager.instance.getFile(_editor.document).path.replaceAll('/java/.*','').replaceAll('/src/','/build/classes/')+' '+_1).execute().text.replaceAll('.*: *','')",qualifiedClassName())

It assumes the standard Gradle project layout. Change /build/ to /target/ for Maven.

score 0 · Answer 13 · answered Jan 16 '23 at 22:31

0

on macOS, you could find where serialVersionUID is applicable.

answered Jan 16 '23 at 22:31

joseluisbz

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IntelliJ IDEA generating serialVersionUID

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