¿Cómo resuelvo el error "java.net.BindException: dirección ya en uso: JVM_Bind"?

En Eclipse, recibí este error: run: [java] Error creating the server socket. [java] Oct 04, 2012 5:31:38 PM cascadas.ace.AceFactory bootstrap [java] SEVERE: Failed to create world : java.net.BindException: Address already in use: JVM_Bind [java] Java Result: -1 BUILD SUCCESSFUL Total time: 10...