How do I compile with -Xlint:unchecked?

Question

I'm getting a message when I compile my code:

Note: H:\Project2\MyGui2.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

How do I recompile with -Xlint:unchecked?

Are you compiling on the command line? If so, add the `-Xlint:unchecked` to the command line you're executing, just as the message indicates. — 101100, Nov 21 '11 at 17:21
depends on how you run your code.. is it from eclipse? command line? — Boaz, Nov 21 '11 at 17:21

score 58 · Accepted Answer · edited Feb 05 '14 at 17:55

58

Specify it on the command line for javac:

javac -Xlint:unchecked

Or if you are using Ant modify your javac target

  <javac ...>
    <compilerarg value="-Xlint"/>
  </javac>

If you are using Maven, configure this in the maven-compiler-plugin

<compilerArgument>-Xlint:unchecked</compilerArgument>

edited Feb 05 '14 at 17:55

guerda

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answered Nov 21 '11 at 17:20

ewan.chalmers

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I have maven 3, model 4.0 -- The `` goes under `` not within the _`'_ element. _Silly me._ – will Jul 16 '16 at 12:45
And what about compile inside AOSP? What should I add to Android.mk file? – Dr.jacky Jul 05 '17 at 06:55

score 54 · Answer 2 · edited Sep 03 '16 at 15:40

54

For IntelliJ 13.1, go to File -> Settings -> Project Settings -> Compiler -> Java Compiler, and on the right-hand side, for Additional command line parameters enter "-Xlint:unchecked".

edited Sep 03 '16 at 15:40

Andrew Tobilko

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answered Jun 12 '14 at 05:04

Brian Burns

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Thanks. But for 13.1 Community Edition it's at File - Settings - Compiler - Java Compiler, and the field is at the bottom. – RenniePet Sep 22 '14 at 22:42
8

For 14.0.3 this settings page has moved to: File - Settings - Build, Execution, Deployment - Compiler - Java Compiler. – csauve Sep 29 '15 at 19:50
1

Not on AndroidStudio, there Compiler options seem to be delivered for *any* compiler, not only Java. Editing **build.gradle** does work. – Alex Cohn Mar 26 '16 at 09:54
In *Android Studio* the compiler options can be found under *File* -> *New Project Settings* -> *Settings for New Projects*. They however seem to **not** be applicable to an existing project. – JJD Aug 16 '20 at 12:09

score 36 · Answer 3 · edited Sep 04 '18 at 10:27

36

In gradle project, You can added this compile parameter in the following way:

gradle.projectsEvaluated {
    tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xlint:unchecked"
    }
}

edited Sep 04 '18 at 10:27

Konrad Rudolph

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answered Jan 07 '14 at 23:09

xianlinbox

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In recent gradle versions the task type `Compile` has been renamed to `JavaCompile`, so it is `tasks.withType(JavaCompile) { ... }` – obecker Oct 23 '17 at 11:25
2

I would add that this should go in `allprojects { // ... }` – Borzh Nov 12 '18 at 15:22
Out of all other options, this is the only that worked for me. Thank you so much – Mohamed El-Beltagy Jun 21 '21 at 22:03

score 24 · Answer 4 · answered Nov 21 '11 at 17:22

24

I know it sounds weird, but I'm pretty sure this is your problem:

Somewhere in MyGui.java you're using a generic collection without specifying the type. For example if you're using an ArrayList somewhere, you are doing this:

List list = new ArrayList();

When you should be doing this:

List<String> list = new ArrayList<String>();

answered Nov 21 '11 at 17:22

Andrew Rasmussen

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1

Thanks a lot,this helped me! – Farb Jul 11 '18 at 06:10
This doesn't even attempt to answer the question given. – hackel Oct 22 '21 at 15:51

score 18 · Answer 5 · edited Sep 05 '14 at 09:05

18

There is another way for gradle:

compileJava {
    options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation"
}

edited Sep 05 '14 at 09:05

Phantom

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answered Sep 05 '14 at 07:55

tarn

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This won't affect the tests for example. – NoDataDumpNoContribution Jun 14 '15 at 21:41
2

For Android Studio, this seems to require a bit different approach: `tasks.withType(JavaCompile) { options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation" }` – Alex Cohn Mar 26 '16 at 09:55
3

for Android Studio 2.1.3 add this to project build.gradle `allprojects { repositories { jcenter() } gradle.projectsEvaluated { tasks.withType(JavaCompile) { options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation" } } }` – tarn Sep 02 '16 at 07:40

score 6 · Answer 6 · answered May 09 '19 at 06:29

6

For Android Studio add the following to your top-level build.gradle file within the allprojects block

tasks.withType(JavaCompile) {
    options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation" 
}

answered May 09 '19 at 06:29

Wirling

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score 3 · Answer 7 · answered Jul 18 '12 at 19:09

3

In CMD, write:

javac -Xlint:unchecked MyGui2.java

it will display the list of unchecked or unsafe operations.

answered Jul 18 '12 at 19:09

Himanshu Aggarwal

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score 3 · Answer 8 · answered Nov 21 '13 at 13:30

If you work with an IDE like NetBeans, you can specify the Xlint:unchecked compiler option in the propertys of your project.

Just go to projects window, right click in the project and then click in Properties.

In the window that appears search the Compiling category, and in the textbox labeled Additional Compiler Options set the Xlint:unchecked option.

Thus, the setting will remain set for every time you compile the project.

score 2 · Answer 9 · edited Aug 16 '20 at 12:06

2

other way to compile using -Xlint:unchecked through command line

javac abc.java -Xlint:unchecked

it will show the unchecked and unsafe warnings.

edited Aug 16 '20 at 12:06

JJD

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answered Oct 16 '13 at 11:53

deepak jaiswal

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score 2 · Answer 10 · edited Aug 16 '20 at 12:06

2

A cleaner way to specify the Gradle compiler arguments follow:

compileJava.options.compilerArgs = ['-Xlint:unchecked','-Xlint:deprecation']

edited Aug 16 '20 at 12:06

JJD

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answered Jan 02 '17 at 00:25

Jim H

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This may be *shorter* but it’s not *cleaner*. For one thing, it overrides existing options set elsewhere. For another, it won’t work affect test, as noted in the comments below tarn’s answer. Don’t do this, use xianlinbox’s answer instead. – Konrad Rudolph Sep 04 '18 at 10:29

score 0 · Answer 11 · edited Jun 05 '17 at 10:52

0

FYI getting to these settings has changed for IntelliJ 15, new and improved for even deeper burial!

Now it's: File > Other Settings > Default Settings > 'Build, Execution, Deployment' > Compiler > Java Compiler

And in Additional command line parameters, same as before, write "-Xlint:unchecked".

edited Jun 05 '17 at 10:52

Ilya Serbis

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answered Jun 02 '16 at 09:03

HAKitz

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How do I compile with -Xlint:unchecked?

11 Answers11

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