org.springframework.dao.InvalidDataAccessApiUsageException: Unexpected AST: org.hibernate.hql.internal.ast.tree.SqlNode 
 \-[NOT] SqlNode: 'not'
    \-[EXISTS] UnaryLogicOperatorNode: 'exists'
       \-[SELECT] QueryNode: 'SELECT'  querySpaces (child,toy)
          +-[SELECT_CLAUSE] SelectClause: '{derived select clause}'
          |  \-[SELECT_EXPR] SelectExpressionImpl: 'toys1_.id' {ImpliedFromElement{implied,not a collection join,not a fetch join,fetch non-lazy properties,classAlias=null,role=com.example.models.Child.toys,tableName=toy,tableAlias=toys1_,origin=child child0_,columns={child0_.id ,className=com.example.models.Toy}}}
          +-[FROM] FromClause: 'from' FromClause{level=2, fromElementCounter=1, fromElements=1, fromElementByClassAlias=[], fromElementByTableAlias=[toys1_], fromElementsByPath=[generatedAlias0.toys], collectionJoinFromElementsByPath=[], impliedElements=[]}
          |  \-[FROM_FRAGMENT] ImpliedFromElement: 'toy toys1_' ImpliedFromElement{implied,not a collection join,not a fetch join,fetch non-lazy properties,classAlias=null,role=com.example.models.Child.toys,tableName=toy,tableAlias=toys1_,origin=child child0_,columns={child0_.id ,className=com.example.models.Toy}}
          \-[WHERE] SqlNode: 'WHERE'
             \-[THETA_JOINS] SqlNode: '{theta joins}'
                \-[SQL_TOKEN] SqlFragment: 'child0_.id=toys1_.child_id'
; nested exception is java.lang.IllegalStateException: Unexpected AST: org.hibernate.hql.internal.ast.tree.SqlNode 
 \-[NOT] SqlNode: 'not'
    \-[EXISTS] UnaryLogicOperatorNode: 'exists'
       \-[SELECT] QueryNode: 'SELECT'  querySpaces (child,toy)
          +-[SELECT_CLAUSE] SelectClause: '{derived select clause}'
          |  \-[SELECT_EXPR] SelectExpressionImpl: 'toys1_.id' {ImpliedFromElement{implied,not a collection join,not a fetch join,fetch non-lazy properties,classAlias=null,role=com.example.models.Child.toys,tableName=toy,tableAlias=toys1_,origin=child child0_,columns={child0_.id ,className=com.example.models.Toy}}}
          +-[FROM] FromClause: 'from' FromClause{level=2, fromElementCounter=1, fromElements=1, fromElementByClassAlias=[], fromElementByTableAlias=[toys1_], fromElementsByPath=[generatedAlias0.toys], collectionJoinFromElementsByPath=[], impliedElements=[]}
          |  \-[FROM_FRAGMENT] ImpliedFromElement: 'toy toys1_' ImpliedFromElement{implied,not a collection join,not a fetch join,fetch non-lazy properties,classAlias=null,role=com.example.models.Child.toys,tableName=toy,tableAlias=toys1_,origin=child child0_,columns={child0_.id ,className=com.example.models.Toy}}
          \-[WHERE] SqlNode: 'WHERE'
             \-[THETA_JOINS] SqlNode: '{theta joins}'
                \-[SQL_TOKEN] SqlFragment: 'child0_.id=toys1_.child_id'

 criteriaBuilder.isNotEmpty 

 criteriaBuilder.isEmpty