/**
     * Get associated {@link DataPoint}s.
     */
    @ElementCollection
    @CollectionTable(name = "DataPoint", joinColumns = @JoinColumn(name = "expant", nullable = false))
    @NotNull
    public Set<DataPoint> getDataPoints() {
        return this.dataPoints;
    }
    public void setDataPoints(Set<DataPoint> dataPoints) {
        this.dataPoints = dataPoints;
    }

Root<Expant> expant = ...
... builder.isNotEmpty(expant.get(Expant_.dataPoints))...

Caused by: java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected end of subtree [select generatedAlias0 from com.example.model.Patient as generatedAlias0 where ( exists (select gen
eratedAlias1 from com.example.model.Patient as generatedAlias2 inner join generatedAlias2.annotations as generatedAlias1 where ( generatedAlias0.id=generatedAlias2.id ) and ( key(generatedAlias1)=:param0 )) ) and ( exists (sel
ect generatedAlias3.id from com.example.model.Expant as generatedAlias3 where ( generatedAlias3.patientId=generatedAlias0.id ) and ( generatedAlias3.experimentUUIDAsString=:param1 ) and ( generatedAlias3.experimentUUIDAsString
=:param2 ) and ( generatedAlias3.dataPoints is not empty )) ) order by generatedAlias0.name.lastName asc, generatedAlias0.name.firstName asc]
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1679)
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1608)
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:551)
        at org.hibernate.jpa.criteria.CriteriaQueryImpl$1.buildCompiledQuery(CriteriaQueryImpl.java:316)
        at org.hibernate.jpa.criteria.compile.CriteriaCompiler.compile(CriteriaCompiler.java:130)
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:699)
        at sun.reflect.GeneratedMethodAccessor353.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298)
        at com.sun.proxy.$Proxy68.createQuery(Unknown Source)
        at org.dellroad.stuff.dao.CriteriaCallback.buildQuery(CriteriaCallback.java:40)
        at org.dellroad.stuff.dao.CriteriaCallback.buildQuery(CriteriaCallback.java:19)
        at org.dellroad.stuff.dao.QueryCallback.query(QueryCallback.java:29)
        at org.dellroad.stuff.spring.AbstractDAO.getBy(AbstractDAO.java:156)
        <other stack frames elided>
        ... 31 more
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected end of subtree [select generatedAlias0 from com.example.model.Patient as generatedAlias0 where ( exists (select generatedAlias1 from com.example.model.Patient as generatedAlias2 inner join generatedAlias2.annotations as generatedAlias1 where ( generatedAlias0.id=generatedAlias2.id ) and ( key(generatedAlias1)=:param0 )) ) and ( exists (select generatedAlias3.id from com.example.model.Expant as generatedAlias3 where ( generatedAlias3.patientId=generatedAlias0.id ) and ( generatedAlias3.experimentUUIDAsString=:param1 ) and ( generatedAlias3.experimentUUIDAsString=:param2 ) and ( generatedAlias3.dataPoints is not empty )) ) order by generatedAlias0.name.lastName asc, generatedAlias0.name.firstName asc]
        at org.hibernate.hql.internal.ast.QuerySyntaxException.generateQueryException(QuerySyntaxException.java:79)
        at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103)
        at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:218)
        at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142)
        at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115)
        at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:76)
        at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:150)
        at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:302)
        at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:240)
        at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1907)
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:531)
        ... 65 more
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected end of subtree
        at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:74)
        at org.hibernate.hql.internal.ast.ErrorCounter.throwQueryException(ErrorCounter.java:91)
        at org.hibernate.hql.internal.ast.QueryTranslatorImpl.generate(QueryTranslatorImpl.java:250)
        at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:210)
        ... 73 more