请按这个结构帮我生成Java领域模型对象，嵌套部分使用内部类的方式：
{
  companyName: 'xxxx',
  billAddress: {
    name: '',
    firstName: '',
    lastName: '',
    address: {
      line1: '',
      line2: '',
      city: '',
      state: '',
      postal_code: '',
      country: ''
    },
    phone: '';
  },
  email: '',
  tax: {
    taxType: '',
    taxId: ''
  }
}