Maven change encoding to certain files

Question

All my project with a Cp1252 encoding, except for a couple of files that I have encoded in UTF-8, which contain special characters.

When I run an install, in those files I get a couple of errors: unclosed character literal, illegal character: '\u00a8'. When doing the install with the plugin with the encoding in UTF8:

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>2.3.2</version>
        <configuration>
            <source>1.8</source>
            <target>1.8</target>
            <encoding>UTF-8</encoding>
        </configuration>
    </plugin>

The error is no longer displayed in the above mentioned files but in many others, the error displayed is: unmappable character for encoding UTF-8.

Can I specify UTF-8 encoding only for some files?

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Another thing, maven displays errors as follows:

folder/file.java:[10,19] unclosed character literal
folder/file.java:[10,22] unclosed character literal
folder/file.java:[13,19] unclosed character literal

What the numbers means? it does not seem to be the line numbers where the error is located.