Use grails service from java class

package com.groovy.exception

import com.services.TestService
import org.springframework.context.ApplicationContext
import org.codehaus.groovy.grails.web.util.WebUtils

/**
 * Created by pritom on 9/02/14.
 */
class CustomException extends RuntimeException {
    private static TestService testService;
    String message;
    List args = [];

    public CustomException(String message, List args) {
        this.message = message;
        this.args = args;
    }

    public String getMessage() {
        return this.toString();
    }

    public List getArgs() {
        return this.args;
    }

    public String toString() {
        String _message = testService.getMessage(this.message, this.args);
        return _message
    }

    static {
        if(!testService) {
            ApplicationContext applicationContext = WebUtils.retrieveGrailsWebRequest().getApplicationContext();
            testService = applicationContext.getBean("testService");
        }
    }
}