No grammar constraints (DTD or XML schema) detected for the document

I got rid of this annoying warning by specifying <!DOCTYPE xml> after the <?xml ... > tag instead of specifying something else (like templates in your case).

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

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This worked for me in Eclipse 3.7.1:

Go to the Preferences window, then XML -> XML Files -> Validation.

Then in the Validating files section of the preferences panel on the right, choose Ignore in the drop down box for the "No grammar specified" preference. You may need to close the file and then reopen it to make the warning go away.

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Answer:

Comments on each piece of your DTD below. Refer to official spec for more info.

  <!
  DOCTYPE ----------------------------------------- correct
  templates --------------------------------------- correct  Name matches root element.
  PUBLIC ------------------------------------------ correct  Accessing external subset via URL.
  "//UNKNOWN/" ------------------------------------ invalid? Seems useless, wrong, out-of-place.
                                                             Safely replaceable by DTD URL in next line.
  "http://fast-code.sourceforge.net/template.dtd" - invalid  URL is currently broken.
  >

Simple Explanation:

An extremely basic DTD will look like the second line here:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE nameOfYourRootElement>
<nameOfYourRootElement>
</nameOfYourRootElement>

Detailed Explanation:

DTDs serve to establish agreed upon data formats and validate the receipt of such data. They define the structure of an XML document, including:

a list of legal elements

special characters

character strings

and a lot more

E.g.

<!DOCTYPE nameOfYourRootElement
[
<!ELEMENT nameOfYourRootElement (nameOfChildElement1,nameOfChildElement2)>
<!ELEMENT nameOfChildElement1 (#PCDATA)>
<!ELEMENT nameOfChildElement2 (#PCDATA)>
<!ENTITY nbsp "&#xA0;"> 
<!ENTITY author "Your Author Name">
]>

Meaning of above lines...
Line 1) Root element defined as "nameOfYourRootElement"
Line 2) Start of element definitions
Line 3) Root element children defined as "nameOfYourRootElement1" and "nameOfYourRootElement2"
Line 4) Child element, which is defined as data type #PCDATA
Line 5) Child element, which is defined as data type #PCDATA
Line 6) Expand instances of   to   when document is parsed by XML parser
Line 7) Expand instances of &author; to Your Author Name when document is parsed by XML parser
Line 8) End of definitions

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The Real Solution:

add <!DOCTYPE something> to the begining of each problematic XML,

after the xml tag <?xml version="1.0" encoding="utf-8"?>

you can write anything for doctype, but basically it's supposed to be manifest, activity, etc. from what I understand

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Have you tried to add a schema to xml catalog?

in eclipse to avoid the "no grammar constraints (dtd or xml schema) detected for the document." i use to add an xsd schema file to the xml catalog under

"Window \ preferences \ xml \ xml catalog \ User specified entries".

Click "Add" button on the right.

Example:

<?xml version="1.0" encoding="UTF-8"?>
<HolidayRequest xmlns="http://mycompany.com/hr/schemas">
    <Holiday>
        <StartDate>2006-07-03</StartDate>
        <EndDate>2006-07-07</EndDate>
    </Holiday>
    <Employee>
        <Number>42</Number>
        <FirstName>Arjen</FirstName>
        <LastName>Poutsma</LastName>
    </Employee>
</HolidayRequest>

From this xml i have generated and saved an xsd under: /home/my_user/xsd/my_xsd.xsd

As Location: /home/my_user/xsd/my_xsd.xsd

As key type: Namespace name

As key: http://mycompany.com/hr/schemas

Close and reopen the xml file and do some changes to violate the schema, you should be notified

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Add DOCTYPE tag ...

In this case:

<!DOCTYPE xml>

Add after:

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

So:

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

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Try understanding the suggestion given in warning messages, it's helps sometime.

I also had the same issues, after doing some research i found the solution and fixed by adding the below line at the beginning

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

which lead to some other issue in my case. Which i solved by reading the suggestions, which again turned into the another problem, which has been solved understanding the original cause, that the first link was broken (not found). Below are the step by step images which explains what has been done to resolve the issue completely.

https://i.stack.imgur.com/ka1dq.jpg

https://i.stack.imgur.com/J9Tak.jpg

https://i.stack.imgur.com/rl8Oq.jpg

https://i.stack.imgur.com/E9fiK.jpg

https://i.stack.imgur.com/c5QjS.jpg

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A new clean way might be to write your xml like so:

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE rootElement>

<rootElement>
 ....
</rootElement>

The above works in Eclipse Juno+

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For me it was a Problem with character encoding and unix filemode running eclipse on Windows:

Just marked the complete code, cutted and pasted it back (in short: CtrlA-CtrlX-CtrlV) and everything was fine - no more "No grammar constraints..." warnings

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I can't really say why you get the "No grammar constraints..." warning, but I can provoke it in Eclipse by completely removing the DOCTYPE declaration. When I put the declaration back and validate again, I get this error message:

The content of element type "template" must match "(description+,variation?,variation-field?,allow-multiple-variation?,class-pattern?,getter-setter?,allowed-file-extensions?,template-body+).

And that is correct, I believe (the "number-required-classes" element is not allowed).

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i know this is old but I'm passing trought the same problem and found the solution in the spring documentation, the following xml configuration has been solved the problem for me.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc" 
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc 
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/tx 

<!-- THIS IS THE LINE THAT SOLVE MY PROBLEM -->
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd 

http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-3.0.xsd">

before I put the line above as sugested in this forum topic , I have the same warning message, and placing this...

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

and it give me the following warning message...

The content of element type "template" must match "
(description,variation?,variation-field?,allow- multiple-variation?,class-
pattern?,getter-setter?,allowed-file-extensions?,number-required- 
classes?,template-body)".

so just try to use the sugested lines of my xml configuration.

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This may be due to turning off validation in eclipse.

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Solved this issue in Eclipse 3.5.2. Two completely identical layouts of which one had the warning. Closed down all tabs and when reopening the warning had disappeared.

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copy your entire code in notepad. temporarily save the file with any name [while saving the file use "encoding" = UTF-8 (or higher but UTF)]. close the file. open it again. copy paste it back on your code.

error must be gone.

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I used a relative path in the xsi:noNamespaceSchemaLocation to provide the local xsd file (because I could not use a namespace in the instance xml).

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="../project/schema.xsd">
</root>

Validation works and the warning is fixed (not ignored).

https://www.w3schools.com/xml/schema_example.asp

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I too had the same problem in eclipse using web.xml file it showed me this " no grammar constraints referenced in the document "

but it can be resolved by adding tag
after the xml tag i.e. <?xml version = "1.0" encoding = "UTF-8"?>

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Here's the working solution for this problem:

Step 1: Right click on project and go to properties

Step 2: Go to 'libraries' and remove the project's ' JRE system library'

Step 3: Click on 'Add library'-->'JRE System Library' -->select 'Workspace default JRE'

Step 3: Go to 'Order and Export' and mark the newly added ' JRE system library'

Step 4: Refresh and Clean the project

Eureka! It's working :)

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What I found to be the solution was something very very simple that I think you should try before tinkering with the preferences. In my case I had this problem in a strings file that had as a base tag "resources" ...all I did was delete the tag from the top and the bottom, clean the project, save the file and reinsert the tag. The problem has since disappeared and never gave me any warnings. It may sound to simple to be true but hey, sometimes it's the simplest things that solve the problems. Cheers

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