http://stackoverflow.com/questions/36863382/

package com.example.foo.test;

import java.lang.reflect.Field;

import javax.annotation.PostConstruct;
import javax.persistence.Entity;
import javax.persistence.metamodel.CollectionAttribute;
import javax.persistence.metamodel.ListAttribute;
import javax.persistence.metamodel.MapAttribute;
import javax.persistence.metamodel.SetAttribute;
import javax.persistence.metamodel.SingularAttribute;
import javax.persistence.metamodel.Type;

import org.hibernate.jpa.internal.metamodel.AbstractAttribute;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
import org.springframework.core.type.filter.AnnotationTypeFilter;
import org.springframework.stereotype.Component;

import com.google.common.base.Throwables;

@Component
@SuppressWarnings({ "rawtypes", "unchecked", "serial" })
public class MockMetaModelGenerator {
    private static final String BASE_PACKAGE = "com.example.foo";

    @PostConstruct
    public void init() {
        ClassPathScanningCandidateComponentProvider scanner = new ClassPathScanningCandidateComponentProvider(false);
        scanner.addIncludeFilter(new AnnotationTypeFilter(Entity.class));
        for (BeanDefinition bd : scanner.findCandidateComponents(BASE_PACKAGE)) {
            Class<?> metamodel;
            try {
                metamodel = Thread.currentThread().getContextClassLoader().loadClass(bd.getBeanClassName() + "_");
                for (Field field : metamodel.getFields()) {
                    field.set(null, new GenericAttrImpl(field.getName()));
                }
            } catch (Exception e) {
                Throwables.propagate(e);
            }
        }
    }

    static class GenericAttrImpl extends AbstractAttribute implements CollectionAttribute, SetAttribute, ListAttribute, MapAttribute, SingularAttribute {

        GenericAttrImpl(String name) {
            super(name, null, null, null, null);
        }

        @Override
        public CollectionType getCollectionType() {
            return null;
        }

        @Override
        public Class getKeyJavaType() {
            return null;
        }

        @Override
        public Type getKeyType() {
            return null;
        }

        @Override
        public Type getElementType() {
            return null;
        }

        @Override
        public boolean isAssociation() {
            return false;
        }

        @Override
        public boolean isCollection() {
            return false;
        }

        @Override
        public BindableType getBindableType() {
            return null;
        }

        @Override
        public Class getBindableJavaType() {
            return null;
        }

        @Override
        public boolean isId() {
            return false;
        }

        @Override
        public boolean isVersion() {
            return false;
        }

        @Override
        public boolean isOptional() {
            return false;
        }

        @Override
        public Type getType() {
            return null;
        }
    }

}