What is enumeration in JSP?

What is enumeration in JSP?

Scriptlets are pieces of Java code embedded in a an HTML page. The example below shows an example scriptlet. The example uses the Enumeration object to get the HTTP headers passed to the server, then displays each header and the data associated with that header. …

How do you create an enumeration?

Example 2

1. import java.util.*;
2. public class CollectionsEnumerationExample2 {
3. public static void main(String[] args) {
4. //Create array list object.
5. List Enum = new ArrayList();
6. Enum.add(1100);
7. Enum.add(2100);
8. Enum.add(5100);

How do you use enumeration in Java?

Example of applying Enum on a switch statement

1. class EnumExample5{
2. enum Day{ SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY}
3. public static void main(String args[]){
4. Day day=Day.MONDAY;
5. switch(day){
6. case SUNDAY:
7. System.out.println(“sunday”);
8. break;

What is enumeration in Java collections with example?

Enumeration interface is one of the predefined interfaces, whose object is used for retrieving the data from collections framework variable( like Stack, Vector, HashTable etc.) The Enumeration Interface defines the functions by which we can enumerate the elements in a collection of elements.

What is difference between Iterator and enumeration?

The main difference between Iterator and Enumeration is removal of the element while traversing the collection. Iterator can remove the element during traversal of collection as it has remove() method. Enumeration does not have remove() method.

Why do we use Enumeration?

Enumerations offer an easy way to work with sets of related constants. An enumeration, or Enum , is a symbolic name for a set of values. Enumerations are treated as data types, and you can use them to create sets of constants for use with variables and properties.

What is the purpose of an Iterator?

The primary purpose of an iterator is to allow a user to process every element of a container while isolating the user from the internal structure of the container. This allows the container to store elements in any manner it wishes while allowing the user to treat it as if it were a simple sequence or list.

What is the purpose of Enumeration or Iterator?

In Iterator, we can read and remove element while traversing element in the collections. Using Enumeration, we can only read element during traversing element in the collections. 2. It can be used with any class of the collection framework.

Which is faster and uses less memory?

Sqldatareader is fast as compare to Dataset. Because it stored data in forward only and also stores only one record at a time. And dataset stores all records at the same time. This is the reason, SqlDataReader is faster than Dataset.

What is the difference between Enumeration text and time order text?

enumeration—literally means numbered “to enumerate”means to list one by one. when used in a literally sense, enumeration is used as a rhetorical device to break a topic or argument down into components part, or to list details of the subject one by one while. about a fast event you need to use time order.

What is difference between vector and ArrayList?

Vector and ArrayList both uses Array internally as data structure. They are dynamically resizable. But, ArrayList increases by half of its size when its size is increased. Therefore as per Java API the only main difference is, Vector’s methods are synchronized and ArrayList’s methods are not synchronized.

Should I use vector or ArrayList?

Performance: ArrayList is faster, since it is non-synchronized, while vector operations give slower performance since they are synchronized (thread-safe). Applications : Most of the time, programmers prefer ArrayList over Vector because ArrayList can be synchronized explicitly using Collections.

Are vectors ArrayList?

Vector: Vector is similar to ArrayList but the differences are, it is synchronized and its default initial size is 10 and when the size exceeds its size increases to double of the original size that means the new size will be 20.

Are vectors like Arraylists?

Vector is similar with ArrayList, but it is synchronized. ArrayList is a better choice if your program is thread-safe. Vector and ArrayList require more space as more elements are added. Vector each time doubles its array size, while ArrayList grow 50% of its size each time.

Are vectors better than arrays?

Vector is better for frequent insertion and deletion, whereas Arrays are much better suited for frequent access of elements scenario. Vector occupies much more memory in exchange for managing storage and growing dynamically, whereas Arrays are a memory-efficient data structure.

Why is linked list better than ArrayList?

Why ArrayList is faster? ArrayList has direct references to every element in the list, so it can get the n-th element in constant time. LinkedList has to traverse the list from the beginning to get to the n-th element. LinkedList is faster than ArrayList for deletion.

What is the difference between vector and ArrayList classes?

ArrayList is non-synchronized. Vector is synchronized. ArrayList increments 50% of its current size if element added exceeds its capacity. Vector increments 100% of its current size if element added exceeds its capacity.

Is ArrayList thread safe?

Any method that touches the Vector ‘s contents is thread safe. ArrayList , on the other hand, is unsynchronized, making them, therefore, not thread safe. With that difference in mind, using synchronization will incur a performance hit. So if you don’t need a thread-safe collection, use the ArrayList .

What does it mean ArrayList is not synchronized?

It means that accessing an ArrayList instance from multiple threads may not be safe (read, “may result in unexpected behavior” or “may not work as advertised”). Further reading: Synchronization and thread safety in Java. Meaning of Java thread safety.