Hibernate Custom validator to validate Multiple email ids

In my current project, i need to validate email ids where user will be enter more email id in one text area with semicolon as separator. Before storing into DB, i need to check whether all the email ids are valid one. So i decided to create custom Hibernate validator constraint. For more examples and understanding, please check here

package com.hibernate;

import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import javax.validation.Constraint;
import javax.validation.Payload;

@Target({ METHOD, FIELD, ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = ValidateEmailValidator.class)
@Documented
public @interface ValidateEmails {

	String message() default "{default message}";

	Class<?>[] groups() default {};

	Class<? extends Payload>[] payload() default {};

}

package com.hibernate;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class ValidateEmailValidator implements
		ConstraintValidator<ValidateEmails, String> {

	String emailPattern = ".+@.+\\.[a-z]+";
	private final Pattern EMAIL_PATTERN = Pattern.compile(emailPattern);

	@Override
	public void initialize(ValidateEmails arg0) {

	}

	@Override
	public boolean isValid(String value,
			ConstraintValidatorContext constraintContext) {
		if (value == null) {
			return true;
		}
		boolean isValid = true;
		String delimiter = ";";
		String[] temp;
		temp = value.split(delimiter);
		for (int i = 0; i < temp.length; i++) {
			if (validateEmail(temp[i]) == false) {
				return false;
			}
		}
		return isValid;
	}

	private boolean validateEmail(String email) {

		return validatePattern(email, EMAIL_PATTERN);
	}

	private boolean validatePattern(String toBeValidated, Pattern pattern) {
		if (toBeValidated == null)
			return false;
		Matcher m = pattern.matcher(toBeValidated);
		return m.matches();
	}
}

Example Usage:

@ValidateEmails(message = "Some email ids are invalid for Send result to email.")
private String resultEmails;