На сайте вместо иконок квадратики как можно исправить

In case you are working with Maven and Apache Wicket also check for the following in order to try to resolve the issue with Font-Awesome and icons not being loaded:

If you have placed your files for example in the following file structure

/src
 /main
  /java
   /your
    /package
     /css
      font-awesome.css
     /font
      fontawesome-webfont.eot
      fontawesome-webfont.svg
      fontawesome-webfont.svgz
      fontawesome-webfont.ttf
      fontawesome-webfont.woff

Check 1) Are you correctly using a Package Resource Guard in order to allow to load the font files correctly?

Example from your class which extends WebApplication:

@Override
public void init() {
    super.init();   
    get().getResourceSettings().setPackageResourceGuard(new PackageResourceGuard());

}

Check 2) After you have made sure that all fonts are correctly transferred to the Web Browser, check for what has been actually transferred to the Web Browser, i.e., did the integrity of the font files change? Compare the files in your source directory and the files transferred to the Web Browser using, e.g., the Web Developer Toolbar of Firefox and DiffDog (for file comparison).

In particular if you are using Maven be aware of resource filtering. Do not filter the folder where your /font files are contained – otherwise they will be corrupted.

Example from your pom.xml

<build>
    <finalName>Your project</finalName>
    <resources>
        <resource>
            <filtering>true</filtering>
            <directory>src/main/resources</directory>
        </resource>
        <resource>
            <filtering>false</filtering>
            <directory>src/main/java</directory>
            <includes>
                <include>**</include>
            </includes>
            <excludes>
                <exclude>**/*.java</exclude>
            </excludes>
        </resource>
    </resources>
</build>

In the example above we do not filter the folder src/main/java, where the css and font files are contained.

For further information on the filtering of binary data please also see the documentation:

http://maven.apache.org/plugins/maven-resources-plugin/examples/filter.html

In particular the documentation warns: “Warning: Do not filter files with
binary content like images! This will most likely result in corrupt output.
If you have both text files and binary files as resources, you need to
declare two mutually exclusive resource sets. The first resource set
defines the files to be filtered and the other resource set defines the
files to copy unaltered…”