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June 29, 2021 Ravi Yasas
@ManyToManyMany to many relationships can be easily mapped by creating another table using @JoinTable as follows.Student entity@Data@Table(name = "Student")@Entitypublic class Student implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO)...
@manytomany / basics / beginners / hibernate / java / jpa / manytomany / mapping / tutorials
June 29, 2021 Ravi Yasas
java.lang.NullPointerExceptionWhen can it be thrown?According to the JavaDoc, the following scenarios can be found.Calling the instance method of a null object.Accessing or modifying the field of a null object.Taking the length of null as if it were an array.Accessing or modifying the slots of null...
basics / beginners / exceptions / java / java8 / nullpointer / optional / toString() / tutorials / value)f()
June 26, 2021 Ravi Yasas
Throw vs throwsThrowThrowsUses inside a method when it is required to throw an exceptionThis is used in the method signature in which methods that exceptions can occur. Only one exception can be thrownThrows can be used to declare multiple exceptionsUsed to handle unchecked exceptionsUsed to handle...
basics / beginners / exception handling / exceptions / java / learning / throw / throws / tutorial
@OneToOne The best approach to bidirectional @OneToOne is to use @MapsId Student entity @Entity @Data @Table(name = "students") pu...
