Error: unmappable character for encoding UTF8

ERROR: error: unmappable character for encoding UTF8

Characteristics: Could be another enconding

Situation: Using ANT as a compiler, JDK 1.7.0_51, Struts2, Eclipse Kepler, Windows 7, Jboss EAP 6.1

Possible solution: On eclipse Go to -> build.xml ->  External Tools Configuration -> Select build.xml -> Common -> change encoding