Google Web Toolkit: September 2017

Saturday, September 30, 2017

Re: Typescript annotations to JsInterop java classes automatic generation tool ready

Really great tool for making GWT applications work with javascript/typescript tools with standard JsInterop API. Thank arnaud.

On Fri, Sep 29, 2017 at 8:09 PM, Arnaud TOURNIER <ltearno@gmail.com> wrote:

Thanks for your message,
Very good idea about transpiling jquery! I was hoping to ship that immediately but jquery shown me darker side of typing defintions with typescript, so there are a lot of bugs I didn't see at first on my tool (angular is written in an oop style) I need to fix now.
Let me get back to you in few days when I got all the details fixed (right now I get 25 java errors out of the jquery .d.ts transpilation which I need to fix by hand, not very handy for such a common case as the jquery lib ;))
I should soon document the code architecture to ease if people want to contribute.
See you
Arnaud

Le jeu. 28 sept. 2017 à 13:00, Vassilis Virvilis <vasvir2@gmail.com> a écrit :
Wow! This is impressive!

I am not familiar with Angular and cannot comment in the quality of the generated API.

Any chance you could post jquery jsinteropified with your tool? jquery is the basis for a lot of libraries so if you get that correctly a lot libaries will be trivial to process.

I skimmed through the README and I like the configuration control. Can it be per class or is a global configuration per .d.ts file?

Thanks for that contribution.

On Thu, Sep 28, 2017 at 12:54 PM, Ltearno <ltearno@gmail.com> wrote:
Hi everyone,

I made up and published today a tool which uses Typescript type definitions (.d.ts) and generates the corresponding JsInterop classes for use inside a GWT application (or JaCL when available).

The tool is here : https://github.com/ltearno/typescript2java

I use it to translate the full Angular 4 API (2000+ classes) into JsInterop and get a working code. It can also generate the standard web api from 'lib.es6.d.ts' and generate something that ressembles Elemental2 a lot!

I am interested to help if people want to use it or have some other use cases (wrapping D3.js or any other library available on 'definitely typed'). So don't hesitate to file an issue on github... Or to answer here!

Thanks
Arnaud

--
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscribe@googlegroups.com.

To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

--
Vassilis Virvilis

--
You received this message because you are subscribed to a topic in the Google Groups "GWT Users" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/google-web-toolkit/5YgpOfYi9H8/unsubscribe.
To unsubscribe from this group and all its topics, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

Friday, September 29, 2017

Re: GWT 2.8.1 NoClassDefFoundError OptionJsInteropMode

More precisely, you probably have a gwt-codeserver.jar from 2.7 (or a backwards compatible equivalent) and a gwt-dev.jar from 2.8.
Actually, gwt-codeserver is useless starting with GWT 2.7, as it's merged into gwt-dev at build time.

--
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

Re: Typescript annotations to JsInterop java classes automatic generation tool ready

Thanks for your message,

Very good idea about transpiling jquery! I was hoping to ship that immediately but jquery shown me darker side of typing defintions with typescript, so there are a lot of bugs I didn't see at first on my tool (angular is written in an oop style) I need to fix now.

Let me get back to you in few days when I got all the details fixed (right now I get 25 java errors out of the jquery .d.ts transpilation which I need to fix by hand, not very handy for such a common case as the jquery lib ;))

I should soon document the code architecture to ease if people want to contribute.

See you

Arnaud

Le jeu. 28 sept. 2017 à 13:00, Vassilis Virvilis <vasvir2@gmail.com> a écrit :

Wow! This is impressive!

I am not familiar with Angular and cannot comment in the quality of the generated API.

Any chance you could post jquery jsinteropified with your tool? jquery is the basis for a lot of libraries so if you get that correctly a lot libaries will be trivial to process.

I skimmed through the README and I like the configuration control. Can it be per class or is a global configuration per .d.ts file?

Thanks for that contribution.

On Thu, Sep 28, 2017 at 12:54 PM, Ltearno <ltearno@gmail.com> wrote:
Hi everyone,

I made up and published today a tool which uses Typescript type definitions (.d.ts) and generates the corresponding JsInterop classes for use inside a GWT application (or JaCL when available).

The tool is here : https://github.com/ltearno/typescript2java

I use it to translate the full Angular 4 API (2000+ classes) into JsInterop and get a working code. It can also generate the standard web api from 'lib.es6.d.ts' and generate something that ressembles Elemental2 a lot!

I am interested to help if people want to use it or have some other use cases (wrapping D3.js or any other library available on 'definitely typed'). So don't hesitate to file an issue on github... Or to answer here!

Thanks
Arnaud

--
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscribe@googlegroups.com.

To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

--
Vassilis Virvilis

--
You received this message because you are subscribed to a topic in the Google Groups "GWT Users" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/google-web-toolkit/5YgpOfYi9H8/unsubscribe.
To unsubscribe from this group and all its topics, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

Re: GWT 2.8.1 NoClassDefFoundError OptionJsInteropMode

The class in question does not exist anymore in GWT 2.8.x, so your IDE somehow still sees GWT 2.7.

Check your class path.

-- J.

GWT 2.8.1 NoClassDefFoundError OptionJsInteropMode

Upgrading from GWT 2.7 to 2.8.1 with a fresh install of Eclipse Oxygen and receive this error when we trying to launch dev mode (sdm). Any ideas?

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/gwt/dev/util/arg/OptionJsInteropMode$Mode

at com.google.gwt.dev.codeserver.Options.<init>(Options.java:81)

at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:45)

Caused by: java.lang.ClassNotFoundException: com.google.gwt.dev.util.arg.OptionJsInteropMode$Mode

at java.net.URLClassLoader.findClass(URLClassLoader.java:381)

at java.lang.ClassLoader.loadClass(ClassLoader.java:424)

at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)

at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

... 2 more

Re: Typescript annotations to JsInterop java classes automatic generation tool ready

Thanks Joseph,

Not right now, I still need to adjust a few things..
I will let you know when Tour of heroes and all other ANgular 2 samples will have been ported to Angular 4

Thanks

Arnaud

Le ven. 29 sept. 2017 à 11:09, Joseph Webber <joseph.webber@gmail.com> a écrit :

This is totally awesome! I have the tour of heros working with angular2 as per a project post by Lte Consulting a year ago. Is there the Angular4 tour of heros example working and published? I work a very large government department that is just starting to use Angular 4 now and i would like to demo doing this in Java.

On Thursday, 28 September 2017 19:24:05 UTC+9:30, Ltearno wrote:
Hi everyone,

I made up and published today a tool which uses Typescript type definitions (.d.ts) and generates the corresponding JsInterop classes for use inside a GWT application (or JaCL when available).

The tool is here : https://github.com/ltearno/typescript2java

I use it to translate the full Angular 4 API (2000+ classes) into JsInterop and get a working code. It can also generate the standard web api from 'lib.es6.d.ts' and generate something that ressembles Elemental2 a lot!

I am interested to help if people want to use it or have some other use cases (wrapping D3.js or any other library available on 'definitely typed'). So don't hesitate to file an issue on github... Or to answer here!

Thanks
Arnaud

--
You received this message because you are subscribed to a topic in the Google Groups "GWT Users" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/google-web-toolkit/5YgpOfYi9H8/unsubscribe.
To unsubscribe from this group and all its topics, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

Re: GWT 2.8.1 Super Dev Mode Out Of Memory

Hi, I have same problem..

we have crash problem in gwt2.8.1 and internet explorer11.

we don't use super dev mode..in the case..we got ie crash.

do you know someone solution?

2017年8月8日火曜日 6時12分38秒 UTC+9 Anand Deshmukh:

Hello All,

We have recently upgraded large enterprise product from GWT 2.7 to 2.8.1 but we are facing huge challenge with Super Dev Mode with getting frequent chrome crash with Out Of Memory errors which were not present in GWT 2.7 compilation. Any typical memory and browser requirements?

Any pointers for this is highly appreciated.

Regards,
Anand

Re: Problems moving JsInterop from GWT 2.7 to 2.8

We have been using this technique for more than a year and it works perfectly. We call it "Java Notation Object", hehe and you should understand the limitations, which more or less you are currently fulfilling. Just a few changes...

The most important, yes, you should use @JsType(isNative=true,namespace=GLOBAL,name="Object"), so you are actually ignoring any kind of typing, so this is more a "scheme" of where to find things than an actual typed object. This is pretty important! This is pretty similar to JSON but in Java, and these classes are not actually Java classes, are just a scheme. All these limitations are the common intersection of the feature between Java and JS.

You can do some tricks to use collections but we end up removing all of them and using arrays instead. But, to make it easy to work with, we added some @JsOverlay to return or set the Collection. For example if you have "String[] roles" you can add "@JsOverlay getRoleSet() { return Stream.of(roles).collecto(toSet()); }". Overlays are ok bc there are just like extension method or static method, so no behavior is added to the object.

This work perfectly on both sides, but there is a small annoying difference between GWT and Java, in java new Foo() will initialize primitive types and in GWT (js) will not. So we never use constructor directly, in the kind of classes we always add a static factory method and we initialize any non-nullable field, even primitives! So in java you are actually creating the object of the specified type, but in JS you are just calling "new Object()", but it is ok, bc where are using a scheme, no a type. And we never use instanceof on these schemes! This will work on the Java side, but I strongly discourage, you should not need to do that.

Finally, we never use getter and setter, don't make sense, you "cannot use inheritance" (you can use with some ticks too, for example using some int or string field as the type indicator and using, for example, the visitor pattern to traverse, this is what actually people need to do in JS so, no magic just the common intersection of features between java and json), almost everything is like final and you must not add behavior, so it is much explicit and easier to just make all field public.

I think the first you should do is removing getters and setters, and add @JsType(native,Object) to all your types, this refactor can be done almost instantly in your IDE (inline method). Then stop using Collection might not be so easy to refactor. So you might continue using it either using overlays or creating a custom jsinterop-compatible type. In this case, I recommend to not to use the whole java.util API bc it will force you to export the whole API and use generateJsInteropExports. If you are really interested or need help there just ask, but just try out avoiding maps, and using arrays. Anyways, the "Map/List own interface" should work too, just neet to make it work.

On Fri, Sep 29, 2017 at 12:53 PM Thomas Broyer <t.broyer@gmail.com> wrote:

On Friday, September 29, 2017 at 11:09:42 AM UTC+2, Jürgen Beringer wrote:
Hey,

currently I tried the 2. time to move our application from gwt 2.7 to gwt 2.8, but I have big problems with the changes of JsInterop.

The application contains a serverside java part, running in a jetty and the client part, build with gwt, so I can reuse many software on server and client side. (It is the main part of the website www.spreadshirt.com )
To use also the same data classes (containing only fields with getter and setter, no other methods) on both sides, I used JsInterop and it works very well with gwt 2.7 and exchanged the data as json.

Example Data class:

@JsType public class MyObject { private String id; @JsProperty public String getId() { return id; } @JsProperty public void setId(String id) { this.id = id; } }

The class can be used on server side like any normal java class with any REST Framework. On gwt side I was able to convert a transmitted json to the class with:

MyObject myObject = getJsTypeObject(JsonUtils.safeEval(jsonString)); //use getter and setter to access fields public static native <T> T getJsTypeObject(JavaScriptObject result)/*-{ return result; }-*/;

And to create Objects on gwt side and send them to the server as json:

MyObject myObject = new MyObject(); myObject.setId("1"); String jsonString = stringify(myObject); public static final native String stringify(Object result) /*-{ return JSON.stringify(result); }-*/;

I also solved the problem of List and Map with an own Interface, which is an ArrayList/HashMap on serverside and an own implemented native List/Map on gwt side.

The application has more than 100 such Objects which are heavily used on server and client side in many methods which are also be used on both sides. So implementing them twice for server and client side would be a big overhead.
Now is my question, how can I convert this gwt 2.7 code to gwt 2.8 (mainly to be able to use Java8 syntax in future). I tried multiple variants, but it seems for me, JsInterop in gwt 2.8 is not planned for such usecases which were possible in gwt 2.7 withou any problems.
I can either use a native Javascript Object in gwt (native=true) or a in GWT created Object in Javascript. But I see no solution to do both with the same Type.

I get 2 Problems
Casting issues: I can't use native=true because I also want to create such Objects on gwt side, so on every assignment (jsonString to typed variable) I get a cast exception and at least in superdev mode I can't deactivate the cast exceptions
If you never do "instanceof" (or expect cast exceptions) on client-side, you could probably use isNative=true,namespace=GLOBAL,name="Object"; that way, all your objects are plain old JS objects (no specific class/constructor is generated in JS), which is actually exactly what you'd expect from JSON.parse().
field name problems: The jsonString of the last example is {"id_g_$3":"1"} and not {"id":"1"} because the JsProperty for getter and setter works only fine with native objects. If I add JsProperty to the field itself, I can't do have JsProperty for the getter and setter, so I have to add JsIgnore to them. But then when I work with native Objects I can't use the getter and setter on gwt side. I would need JsProperty on getter, setter and the field itself, but this is also not allowed.

The "id_g_$3" is probably because you don't -generateJsInteropExports; contrary to 2.7, in 2.8, the "don't obfuscate @JsProperty/@JsMethod names" only applies when you -generateJsInteropExports.
But if you switch to isNative=true,namespace=GLOBAL,name="Object", you don't even need it.

--
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscribe@googlegroups.com.
To post to this group, send email to google-web-toolkit@googlegroups.com.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.

Re: Problems moving JsInterop from GWT 2.7 to 2.8

On Friday, September 29, 2017 at 11:09:42 AM UTC+2, Jürgen Beringer wrote:

Hey,

currently I tried the 2. time to move our application from gwt 2.7 to gwt 2.8, but I have big problems with the changes of JsInterop.

The application contains a serverside java part, running in a jetty and the client part, build with gwt, so I can reuse many software on server and client side. (It is the main part of the website www.spreadshirt.com )
To use also the same data classes (containing only fields with getter and setter, no other methods) on both sides, I used JsInterop and it works very well with gwt 2.7 and exchanged the data as json.

Example Data class:

@JsType public class MyObject { private String id; @JsProperty public String getId() { return id; } @JsProperty public void setId(String id) { this.id = id; } }

The class can be used on server side like any normal java class with any REST Framework. On gwt side I was able to convert a transmitted json to the class with:

MyObject myObject = getJsTypeObject(JsonUtils.safeEval(jsonString)); //use getter and setter to access fields public static native <T> T getJsTypeObject(JavaScriptObject result)/*-{ return result; }-*/;

And to create Objects on gwt side and send them to the server as json:

MyObject myObject = new MyObject(); myObject.setId("1"); String jsonString = stringify(myObject); public static final native String stringify(Object result) /*-{ return JSON.stringify(result); }-*/;

I also solved the problem of List and Map with an own Interface, which is an ArrayList/HashMap on serverside and an own implemented native List/Map on gwt side.

The application has more than 100 such Objects which are heavily used on server and client side in many methods which are also be used on both sides. So implementing them twice for server and client side would be a big overhead.
Now is my question, how can I convert this gwt 2.7 code to gwt 2.8 (mainly to be able to use Java8 syntax in future). I tried multiple variants, but it seems for me, JsInterop in gwt 2.8 is not planned for such usecases which were possible in gwt 2.7 withou any problems.
I can either use a native Javascript Object in gwt (native=true) or a in GWT created Object in Javascript. But I see no solution to do both with the same Type.

I get 2 Problems
Casting issues: I can't use native=true because I also want to create such Objects on gwt side, so on every assignment (jsonString to typed variable) I get a cast exception and at least in superdev mode I can't deactivate the cast exceptions

If you never do "instanceof" (or expect cast exceptions) on client-side, you could probably use isNative=true,namespace=GLOBAL,name="Object"; that way, all your objects are plain old JS objects (no specific class/constructor is generated in JS), which is actually exactly what you'd expect from JSON.parse().

field name problems: The jsonString of the last example is {"id_g_$3":"1"} and not {"id":"1"} because the JsProperty for getter and setter works only fine with native objects. If I add JsProperty to the field itself, I can't do have JsProperty for the getter and setter, so I have to add JsIgnore to them. But then when I work with native Objects I can't use the getter and setter on gwt side. I would need JsProperty on getter, setter and the field itself, but this is also not allowed.

The "id_g_$3" is probably because you don't -generateJsInteropExports; contrary to 2.7, in 2.8, the "don't obfuscate @JsProperty/@JsMethod names" only applies when you -generateJsInteropExports.

But if you switch to isNative=true,namespace=GLOBAL,name="Object", you don't even need it.

Problems moving JsInterop from GWT 2.7 to 2.8

Hey,

currently I tried the 2. time to move our application from gwt 2.7 to gwt 2.8, but I have big problems with the changes of JsInterop.

The application contains a serverside java part, running in a jetty and the client part, build with gwt, so I can reuse many software on server and client side. (It is the main part of the website www.spreadshirt.com )
To use also the same data classes (containing only fields with getter and setter, no other methods) on both sides, I used JsInterop and it works very well with gwt 2.7 and exchanged the data as json.

Example Data class:

@JsType
public class MyObject {
    private String id;
    
    @JsProperty
    public String getId() {
        return id;
    }
    @JsProperty
    public void setId(String id) {
        this.id = id;
    }
}

The class can be used on server side like any normal java class with any REST Framework. On gwt side I was able to convert a transmitted json to the class with:

MyObject myObject = getJsTypeObject(JsonUtils.safeEval(jsonString));
//use getter and setter to access fields

public static native <T> T getJsTypeObject(JavaScriptObject result)/*-{
    return result;
}-*/;

And to create Objects on gwt side and send them to the server as json:

MyObject myObject = new MyObject();
myObject.setId("1");
String jsonString = stringify(myObject);


public static final native String stringify(Object result) /*-{
    return JSON.stringify(result);
}-*/;

I also solved the problem of List and Map with an own Interface, which is an ArrayList/HashMap on serverside and an own implemented native List/Map on gwt side.

The application has more than 100 such Objects which are heavily used on server and client side in many methods which are also be used on both sides. So implementing them twice for server and client side would be a big overhead.
Now is my question, how can I convert this gwt 2.7 code to gwt 2.8 (mainly to be able to use Java8 syntax in future). I tried multiple variants, but it seems for me, JsInterop in gwt 2.8 is not planned for such usecases which were possible in gwt 2.7 withou any problems.
I can either use a native Javascript Object in gwt (native=true) or a in GWT created Object in Javascript. But I see no solution to do both with the same Type.

I get 2 Problems

Casting issues: I can't use native=true because I also want to create such Objects on gwt side, so on every assignment (jsonString to typed variable) I get a cast exception and at least in superdev mode I can't deactivate the cast exceptions
field name problems: The jsonString of the last example is {"id_g_$3":"1"} and not {"id":"1"} because the JsProperty for getter and setter works only fine with native objects. If I add JsProperty to the field itself, I can't do have JsProperty for the getter and setter, so I have to add JsIgnore to them. But then when I work with native Objects I can't use the getter and setter on gwt side. I would need JsProperty on getter, setter and the field itself, but this is also not allowed.

Is there any solution for me? I love the idea to run the same code in a normal java webapplication and to compile it gwt to run it on client side (the gwt compiler produces very optimized js code and support code splitting, remote logging with java stacktraces and debugging on live website with superdev). I don't want to compile java code to js to run it with nodejs on serverside.

Thanks a lot,
Jürgen

Thursday, September 28, 2017

Re: Typescript annotations to JsInterop java classes automatic generation tool ready

This is totally awesome! I have the tour of heros working with angular2 as per a project post by Lte Consulting a year ago. Is there the Angular4 tour of heros example working and published? I work a very large government department that is just starting to use Angular 4 now and i would like to demo doing this in Java.

On Thursday, 28 September 2017 19:24:05 UTC+9:30, Ltearno wrote:

Hi everyone,

I made up and published today a tool which uses Typescript type definitions (.d.ts) and generates the corresponding JsInterop classes for use inside a GWT application (or JaCL when available).

The tool is here : https://github.com/ltearno/typescript2java

I use it to translate the full Angular 4 API (2000+ classes) into JsInterop and get a working code. It can also generate the standard web api from 'lib.es6.d.ts' and generate something that ressembles Elemental2 a lot!

I am interested to help if people want to use it or have some other use cases (wrapping D3.js or any other library available on 'definitely typed'). So don't hesitate to file an issue on github... Or to answer here!

Thanks
Arnaud

Re: Typescript annotations to JsInterop java classes automatic generation tool ready

Great! That will be absolutely must have tool, thank you.

On Thursday, September 28, 2017 at 2:54:05 AM UTC-7, Ltearno wrote:

Hi everyone,

I made up and published today a tool which uses Typescript type definitions (.d.ts) and generates the corresponding JsInterop classes for use inside a GWT application (or JaCL when available).

The tool is here : https://github.com/ltearno/typescript2java

I use it to translate the full Angular 4 API (2000+ classes) into JsInterop and get a working code. It can also generate the standard web api from 'lib.es6.d.ts' and generate something that ressembles Elemental2 a lot!

I am interested to help if people want to use it or have some other use cases (wrapping D3.js or any other library available on 'definitely typed'). So don't hesitate to file an issue on github... Or to answer here!

Thanks
Arnaud

Re: Looking for a List of all GWT Modules.

From the post above, I don't think the list would be listed here neither.

http://www.gwtproject.org/javadoc/latest/index.html?overview-summary.html

Thank you.

On Thursday, September 28, 2017 at 9:03:06 AM UTC-7, Ananchai Srirochanakul wrote:

Hi,

I am looking for a list of all GWT modules. I tried searching from the internet, but I could not find it. I could not find it here neither http://www.gwtproject.org/doc/latest/DevGuide.html.
I also learn that GWT modules share some similarities with Java packages, but they are not the same thing.

https://support.google.com/code/answer/55197?hl=en

The example of GWT modules used in my project are below.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.8.1//EN"
"http://gwtproject.org/doctype/2.8.1/gwt-module.dtd">
<module rename-to='index'>

<inherits name='com.google.gwt.core.Core'/>
<inherits name='com.google.gwt.user.User'/>
<inherits name="com.google.gwt.i18n.I18N"/>
<inherits name="com.google.gwt.i18n.CldrLocales"/>
<inherits name="com.google.gwt.user.theme.clean.CleanResources"/>
<inherits name="com.google.gwt.user.theme.standard.StandardResources"/>
<inherits name="com.google.gwt.user.theme.chrome.ChromeResources"/>
<inherits name="com.google.gwt.user.theme.dark.DarkResources"/>

I hope someone can help.

Thank you.