Compilation problem for java enums defined as groovy classes

Hi, I have following groovy class TransactionStatus.groovy with code:

package com.webbfontaine.twm.accounting.epaylog.emess.model.response

public enum TransactionStatus {
OK, ERROR
}

and compilation of this class using groovy 1.8.4 was ok but after migrating to 1.8.5 I have following:

groovy.compile:
[mkdir] Created dir: /home/sargis/projects/twm3.git/modules/accounting/Server/classes
[groovyc] Compiling 186 source files to /home/sargis/projects/twm3.git/modules/accounting/Server/classes
[groovyc] org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
[groovyc] Compile error during compilation with javac.
[groovyc] warning: [options] bootstrap class path not set in conjunction with -source 1.6
[groovyc] /tmp/groovy-generated-3682106614822967278-java-source/com/webbfontaine/twm/accounting/epaylog/emess/model/response/TransactionStatus.java:10: error: modifier final not allowed here
[groovyc] public final enum TransactionStatus
[groovyc] ^
[groovyc] Note: Some input files use or override a deprecated API.
[groovyc] Note: Recompile with -Xlint:deprecation for details.
[groovyc] Note: Some input files use unchecked or unsafe operations.
[groovyc] Note: Recompile with -Xlint:unchecked for details.
[groovyc] 1 error
[groovyc] 1 warning
[groovyc]
[groovyc]
[groovyc] 1 error

I am using

<taskdef name="groovyc" classname="org.codehaus.groovy.ant.Groovyc">

</taskdef>

to compile groovy codes of my project.