"org.hibernate.QueryException: could not resolve property: null ..." in Hibernate

Issue

• An entity is defined with a composite (multi-property) identifier/key

  @Entity(name = "Person")
  @IdClass(PersonId.class)
  public static class Person implements Serializable {
      @Id
      private String name;
  
      @Id
      private int index;
  
      private Integer id;
  }
  

• Executing a query against the id property:

  s.createQuery( "from Person p where p.id is null", Person.class ).list();
  

• An exception is raised

  ... org.hibernate.QueryException: could not resolve property: null of: org.test.entities.Person
      at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:73)
      at org.hibernate.persister.entity.AbstractPropertyMapping.toColumns(AbstractPropertyMapping.java:88)
      at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:43)
      at org.hibernate.persister.entity.AbstractEntityPersister.toColumns(AbstractEntityPersister.java:1952)
      at org.hibernate.hql.internal.ast.tree.FromElementType.toColumns(FromElementType.java:442)
      at org.hibernate.hql.internal.ast.tree.FromElementType.toColumns(FromElementType.java:408)
      at org.hibernate.hql.internal.ast.tree.FromElement.toColumns(FromElement.java:513)
      at org.hibernate.hql.internal.ast.tree.FromElement.getIdentityColumns(FromElement.java:344)
      at org.hibernate.hql.internal.ast.tree.IdentNode.resolveAsAlias(IdentNode.java:198)
      at org.hibernate.hql.internal.ast.tree.IdentNode.resolve(IdentNode.java:124)
      at org.hibernate.hql.internal.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:1045)
      at org.hibernate.hql.internal.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:1033)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.addrExpr(HqlSqlBaseWalker.java:5080)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.addrExprLhs(HqlSqlBaseWalker.java:5614)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.addrExpr(HqlSqlBaseWalker.java:4987)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.expr(HqlSqlBaseWalker.java:1286)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.exprOrSubquery(HqlSqlBaseWalker.java:4706)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.comparisonExpr(HqlSqlBaseWalker.java:4174)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.logicalExpr(HqlSqlBaseWalker.java:2138)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.whereClause(HqlSqlBaseWalker.java:815)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:609)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:313)
      at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:261)
      at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:271)
      at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:191)
      ...