[standalone@localhost:9999 subsystem=logging] /subsystem=logging/console-handler=CONSOLE/:write-attribute(name="encoding", value="UTF-8")
{
    "outcome" => "failed",
    "failure-description" => "JBAS011525: Failed to set handler encoding.",
    "rolled-back" => true
}

21:09:31,256 ERROR [org.jboss.as.controller] (Remoting "ssilvert-win7:MANAGEMENT" task-14) Operation ("write-attribute") failed - address: ([
    ("subsystem" => "logging"),
    ("console-handler" => "CONSOLE")
]) - failure description: "JBAS011525: Failed to set handler encoding."