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Difference between FetchType LAZY and EAGER in Java Persistence API?

I am a newbie to Java Persistence API and Hibernate. What is the difference between FetchType.LAZY and FetchType.EAGER in Java Persistence API? Answer Sometimes you have two entities and there’s a relationship between them. For example, you might have an entity called University and another entity called Student and a University might have many Students: The University entity might have

What are the differences between ArrayList and Vector?

What are the differences between the two data structures ArrayList and Vector, and where should you use each of them? Answer Differences Vectors are synchronized, ArrayLists are not. Data Growth Methods Use ArrayLists if there is no specific requirement to use Vectors. Synchronization If multiple threads access an ArrayList concurrently then we must externally synchronize the block of code which

String assembly by StringBuilder vs StringWriter and PrintWriter

I recently encountered an idiom I haven’t seen before: string assembly by StringWriter and PrintWriter. I mean, I know how to use them, but I’ve always used StringBuilder. Is there a concrete reason for preferring one over the other? The StringBuilder method seems much more natural to me, but is it just style? I’ve looked at several questions here (including

String, StringBuffer, and StringBuilder

Please tell me a real time situation to compare String, StringBuffer, and StringBuilder? Answer Mutability Difference: String is immutable, if you try to alter their values, another object gets created, whereas StringBuffer and StringBuilder are mutable so they can change their values. Thread-Safety Difference: The difference between StringBuffer and StringBuilder is that StringBuffer is thread-safe. So when the application needs

How is a constructor executed?

I am making some revisions from the lecture slides and it says a constructor is executed in the following way: If the constructor starts with this, recursively execute the indicated constructor, then go to step 4. Invoke the explicitly or implicitly indicated superclass constructor (unless this class is java.lang.Object). Initialise the fields of the object in the order in which