Question: HTML5 allows some tags to be written more liberally i.e without corresponding END tags. e.g. `input` need not be closed `</input>`.However if choose **template mode** `HTML5` in Thymeleaf the Thymeleaf engine complains about this and does not parse the HTML template. I want to override this default Strict tag checking behavior. i.e Thymeleaf should parse an HTML template with meta and input (AND ALIKE) tags WITHOUT THEIR RESP. CLOSING TAGS. Pl. guide.

It also complains when you have something like this 

```
<a href="/home/pic/image.png" download="/path/to/file" data-gallery></a>

```

It throws an exception when it encounters the **data-gallery** throws "should be followed by '=' " which is kind of annoying as it takes the flexibility out of HTML5.

Answer: 
All you have to do is run Thymeleaf in "LEGACYHTML5" mode and it works like a charm. Thanks to [this](https://github.com/spring-projects/spring-boot/issues/1270) and [this](http://forum.thymeleaf.org/HTML-tags-strict-checking-td4028045.html) post, I found the solution and am documenting in SO so others do not have to go through the same trouble in finding this answer.

To set the legacy mode you can define the bean in your Spring XML file:

```
<!-- View TemplateResolver -->
<bean id="templateResolver" class="org.thymeleaf.templateresolver.ServletContextTemplateResolver">
    <property name="templateMode" value="LEGACYHTML5"/>
    <property name="cacheable" value="false"/>
</bean>

```

or add the properties to the application.properties file:

```
spring.thymeleaf.mode=LEGACYHTML5
spring.thymeleaf.cache=false

```

And in both cases you have to add the `nekohtml` jar to your project or, if you are running maven, you can add its dependency to your pom.xml

```
<dependency>
     <groupId>net.sourceforge.nekohtml</groupId>
     <artifactId>nekohtml</artifactId>
     <version>1.9.21</version>
 </dependency>

```

Gradle

```
'net.sourceforge.nekohtml:nekohtml:1.9.21'

```
Using `LEGACYHTML5` worked for me as well. 

Also it is necessary to add 

```
<dependency>
    <groupId>net.sourceforge.nekohtml</groupId>
    <artifactId>nekohtml</artifactId>
</dependency>

```

to pom.xml as stated above. But there is one more step which might occur. After doing those two steps I was getting: 

```
java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal

```

To avoid this it is necessary to add

```
<dependency> 
    <groupId>xml-apis</groupId>
    <artifactId>xml-apis</artifactId>
    <version>1.4.01</version>
</dependency>

```

to pom.xml