What is the default constructor in Hibernate POJO?
All persistent classes must have a default constructor (which can be non-public) so that Hibernate can instantiate them using Constructor. newInstance() . It is recommended that you have a default constructor with at least package visibility for runtime proxy generation in Hibernate.
What is the default annotation for a property in Hibernate?
The default annotation for a property in the Java framework is a @ld annotation, where Hibernate assumes that the annotation is on the object’s access properties and detects that it is on the field.
What is @transient in Hibernate?
@Transient annotation in JPA or Hibernate is used to indicate that a field is not to be persisted or ignore fields to save in the database. @Transient exist in javax. persistence package. It is used to annotate a property or field of an entity class, mapped superclass, or embeddable class.
Why do we use POJO class in Hibernate?
POJOs in Hibernate are those which maps its attributes with the corresponding columns of the relational database. Such java object to table mapping is possible with the help of Hibernate as ORM tool. Pojo classes should compiled by compiler directly without take support of other API jar files set at classPath.
Why Hibernate entity needs default constructor?
Reason: Default constructor is required to have Hibernate initialize the entity; private is allowed but package private (or public) visibility is required for runtime proxy generation and efficient data retrieval without bytecode instrumentation.
What is persist method?
Save() and persist() both methods are used for saving object in the database. As per docs − Save() − Persist the given transient instance, first assigning a generated identifier. (Or using the current value of the identifier property if the assigned generator is used.)
What does @transient annotation mean?
@Transient annotation is used to mark a field to be transient for the mapping framework, which means the field marked with @Transient is ignored by mapping framework and the field not mapped to any database column (in RDBMS) or Document property (in NOSQL).
What does @transient do in Java?
transient is a variables modifier used in serialization. At the time of serialization, if we don’t want to save value of a particular variable in a file, then we use transient keyword. When JVM comes across transient keyword, it ignores original value of the variable and save default value of that variable data type.