| Types java app |
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| Data Types and Operators |
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| (Primitive Data Types) |
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| (Non-Primitive Data Types) |
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| Control Flow Statements |
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| Conditional Statements |
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| Looping Statements |
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| Branching Statements |
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| Object-Oriented Programming (OOP) |
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| Classes and Objects |
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| Inheritance |
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| Polymorphism |
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| Encapsulation |
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| Abstraction |
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| Exception Handling |
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| Introduction to Exceptions |
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| Collections Framework |
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| Overview of Collections |
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| Commonly Used Collections |
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| Iterators |
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| Java I/O |
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| File Handling |
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| Serialization |
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| Multithreading |
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| Introduction to Threads |
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| Thread Synchronization |
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| GUI Programming with Swing |
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| Introduction to Swing |
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| Event Handling |
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| Advanced Topics |
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| Java Database Connectivity (JDBC) |
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| JAVA CODE |
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Java Basics
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Working with Objects
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Arrays, Conditionals, and Loops
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Creating Classes and Applications in Java
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More About Methods
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Java Applet Basics
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Graphics, Fonts, and Color
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Simple Animation and Threads
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More Animation, Images, and Sound
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Managing Simple Events and Interactivity
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Creating User Interfaces with the awt
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Windows, Networking, and Other Tidbits
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Modifiers, Access Control, and Class Design
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Packages and Interfaces
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Exceptions
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Multithreading
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Streams and I/O
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Using Native Methods and Libraries
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Under the Hood
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Java Programming Tools
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Working with Data Structures in Java
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Advanced Animation and Media
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Fun with Image Filters
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Client/Server Networking in Java
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Emerging Technologies
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appendix A :- Language Summary
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appendix B :- Class Hierarchy Diagrams
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appendix C The Java Class Library
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appendix D Bytecodes Reference
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appendix E java.applet Package Reference
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appendix F java.awt Package Reference
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appendix G java.awt.image Package Reference
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appendix H java.awt.peer Package Reference
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appendix I java.io Package Reference
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appendix J java.lang Package Reference
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appendix K java.net Package Reference
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appendix L java.util Package Reference
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In Java, Iterator and ListIterator are interfaces used for iterating over collections. They provide different functionalities and are used in various scenarios. Here’s a detailed explanation of both, along with examples:
'Iterator'
The Iterator interface provides methods to iterate over any collection (e.g., ArrayList, HashSet). It allows only forward traversal and is not limited to lists.
Key Methods:
hasNext(): Returnstrueif the iteration has more elements.next(): Returns the next element in the iteration.remove(): Removes the last element returned by the iterator (optional operation).
Example:
import java.util.ArrayList;
import java.util.Iterator;
public class IteratorExample {
public static void main(String[] args) {
// Creating an ArrayList
ArrayList<String> list = new ArrayList<>();
list.add("A");
list.add("B");
list.add("C");
list.add("D");
// Getting the Iterator
Iterator<String> iterator = list.iterator();
// Traversing elements using Iterator
while (iterator.hasNext()) {
String element = iterator.next();
System.out.println(element);
// Removing an element using Iterator
if (element.equals("C")) {
iterator.remove();
}
}
// Displaying the list after removal
System.out.println("List after removal: " + list);
}
}
'ListIterator'
The ‘ListIterator‘ interface extends ‘Iterator‘ and provides additional methods to iterate over lists. It allows bidirectional traversal (both forward and backward) and supports more operations.
Key Methods:
hasNext(): Returnstrueif the list iterator has more elements when traversing the list in the forward direction.next(): Returns the next element in the list and advances the cursor position.hasPrevious(): Returnstrueif the list iterator has more elements when traversing the list in the reverse direction.previous(): Returns the previous element in the list and moves the cursor position backwards.add(E e): Inserts the specified element into the list (optional operation).set(E e): Replaces the last element returned bynext()orprevious()with the specified element (optional operation).remove(): Removes the last element returned bynext()orprevious()(optional operation).
Example:
import java.util.ArrayList;
import java.util.ListIterator;
public class ListIteratorExample {
public static void main(String[] args) {
// Creating an ArrayList
ArrayList<String> list = new ArrayList<>();
list.add("A");
list.add("B");
list.add("C");
list.add("D");
// Getting the ListIterator
ListIterator<String> listIterator = list.listIterator();
// Traversing elements forward using ListIterator
System.out.println("Forward Traversal:");
while (listIterator.hasNext()) {
String element = listIterator.next();
System.out.println(element);
// Adding an element using ListIterator
if (element.equals("B")) {
listIterator.add("E");
}
}
// Traversing elements backward using ListIterator
System.out.println("Backward Traversal:");
while (listIterator.hasPrevious()) {
String element = listIterator.previous();
System.out.println(element);
// Replacing an element using ListIterator
if (element.equals("C")) {
listIterator.set("F");
}
}
// Displaying the list after modifications
System.out.println("List after modifications: " + list);
}
}
'Differences' Between 'Iterator' and ListIterator
1. Direction:
- ‘
Iterator‘ allows only forward traversal. - ‘
ListIterator‘ allows both forward and backward traversal.
2. Operations:
- ‘
Iterator‘ supports basic operations like ‘hasNext()', ‘next()‘, and ‘remove()‘. - ‘
ListIterator‘ supports additional operations like ‘hasPrevious()‘, ‘previous()‘, ‘add(E e)‘, and ‘set(E e)‘.
3. Applicability:
- ‘
Iterator‘ can be used with any collection that implements the ‘Iterable‘ interface. - ‘
ListIterator‘ can be used only with lists (‘List‘ interface).
These interfaces are essential for navigating and manipulating collections in Java, offering different levels of control and functionality.
