"unmappable character for encoding" warning in Java

Try with: javac -encoding ISO-8859-1 file_name.java

Use the "\uxxxx" escape format.

According to Wikipedia, the copyright symbol is unicode U+00A9 so your line should read:

String copyright = "\u00a9 2003-2008 My Company. All rights reserved.";

If you're using Maven, set the <encoding> explicitly in the compiler plugin's configuration, e.g.

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

This helped for me:

All you need to do, is to specify a envirnoment variable called JAVA_TOOL_OPTIONS. If you set this variable to -Dfile.encoding=UTF8, everytime a JVM is started, it will pick up this information.

Source: http://whatiscomingtomyhead.wordpress.com/2012/01/02/get-rid-of-unmappable-character-for-encoding-cp1252-once-and-for-all/

put this line in yor file .gradle above the Java conf.

apply plugin: 'java'
compileJava {options.encoding = "UTF-8"}   

Most of the time this compile error comes when unicode(UTF-8 encoded) file compiling

javac -encoding UTF-8 HelloWorld.java

and also You can add this compile option to your IDE ex: Intellij idea (File>settings>Java Compiler) add as additional command line parameter

https://i.stack.imgur.com/eqbY6.png

-encoding : encoding Set the source file encoding name, such as EUC-JP and UTF-8.. If -encoding is not specified, the platform default converter is used. (DOC)

Gradle Steps

If you are using Gradle then you can find the line that applies the java plugin:

apply plugin: 'java'

Then set the encoding for the compile task to be UTF-8:

compileJava {options.encoding = "UTF-8"}   

If you have unit tests, then you probably want to compile those with UTF-8 too:

compileTestJava {options.encoding = "UTF-8"}

Overall Gradle Example

This means that the overall gradle code would look something like this:

apply plugin: 'java'
compileJava {options.encoding = "UTF-8"}
compileTestJava {options.encoding = "UTF-8"}

This worked for me:

<?xml version="1.0" encoding="utf-8" ?>
<project name="test" default="compile">
    <target name="compile">
        <javac srcdir="src" destdir="classes" encoding="iso-8859-1" debug="true" />
    </target>
</project>

For those wondering why this happens on some systems and not on others (with the same source, build parameters, and so on), check your LANG environment variable. I get the warning/error when LANG=C.UTF-8, but not when LANG=en_US.UTF-8.

If you use eclipse (Eclipse can put utf8 code for you even you write utf8 character. You will see normal utf8 character when you programming but background will be utf8 code) ;

Select Project Right click and select Properties Select Resource on Resource Panel(Top of right menu which opened after 2.) You can see in Resource Panel, Text File Encoding, select other which you want

P.S : this will ok if you static value in code. For Example String test = "İİİİİııııııççççç";

I had the same problem, where the character index reported in the java error message was incorrect. I narrowed it down to the double quote characters just prior to the reported position being hex 094 (cancel instead of quote, but represented as a quote) instead of hex 022. As soon as I swapped for the hex 022 variant all was fine.

If one is using Maven Build from the command prompt one can use the following command as well:

                    mvn -Dproject.build.sourceEncoding=UTF-8