Caused by: java.util.ConcurrentModificationException
	at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:819)
	at java.util.ArrayList$Itr.remove(ArrayList.java:805)
	at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1696)
	at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1424)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1844)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:843)
	at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:399)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:842)
	at org.hibernate.jpa.HibernatePersistenceProvider.createContainerEntityManagerFactory(HibernatePersistenceProvider.java:150)
	at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:67)
	at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:288)
	at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:310)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1571)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1509)
	... 40 more

package model;

import java.util.Map;
import java.util.TreeMap;

import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.MapKeyColumn;
import javax.persistence.Version;

@Entity
public class Data {

    @Version
    private Integer version;

    public Data() {
    }

    @Id
    private String id;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @ElementCollection(fetch = FetchType.LAZY)
    @MapKeyColumn(name = "key")
    private Map<String, GenericStringList> stringlist = new TreeMap<>();

}

package model;

import java.util.LinkedList;
import java.util.List;

import javax.persistence.Embeddable;
import javax.persistence.FetchType;
import javax.persistence.OneToMany;

@Embeddable
public class GenericStringList {

    @OneToMany(fetch = FetchType.LAZY)
    public List<String> stringList = new LinkedList<>();
}