Introduction: Banking Application – Store customer’s information and transactions information. Customers use Banking application to communicate with Banking Employee. How to store information in application? What are Data Structures? Use? Linear Data Structures: arrange the data sequentially in which elements are connected to its previous and next adjacent. Non-Linear Data Structures: in which one …
Collection Hierarchy: The following diagram represents interfaces and classes available in java Collection Framework Define Array and Collection: Define List, Set and Map: List Set Map List is index based. Set is not index based. Map is not index based. List allow duplicates. Set doesn’t allow duplicates. Map store elements using keys. Keys must be …
Wrapper classes: Note: for every primitive type there is a wrapper class in java Primitive type Wrapper class byte Byte short Short int Integer long Long char Character float Float double Double boolean Boolean Boxing: Conversion of primitive type into object type int x = 10; Integer obj = new Integer(x); Un boxing: Conversion of …
Generics: Collection without Generics: Allow to store any type of Objects. Syntax: Collection c = new Collection(); c.add(10); c.add(23.45); c.add(“java”); Collection with Generics: Allow only specific type of data Objects. Syntax: Collection<Integer> c = new Collection<Integer>(); c.add(10); c.add(“java”); // Error : Collection with Generics that allows any type of object: Syntax: Collection<Object> c = new …
ArrayList: Methods: Name Description int size() Returns the number of elements in this list. boolean add(E e) Appends the specified element to the end of this list Object remove(int index) Removes the element at the specified position in this list void clear() Removes all of the elements from this list void add(int index, E element) …
Program to display ArrayList and its size: import java.util.*;class Code{ public static void main(String[] args) { List<Integer> list = new ArrayList<Integer>(); list.add(10); list.add(20); list.add(30); list.add(40); list.add(50); System.out.println(“List is : ” + list); System.out.println(“Size is : ” + list.size()); }} Program to check the list is empty or not: import java.util.*;class Code{ public static void main(String[] …
For-each loop: Limitations: Syntax: for (datatype var : Array/Collection ){ statements ;} Program to display ArrayList using for-each loop: import java.util.*;class Code{ public static void main(String[] args) { List<Integer> list = new ArrayList<Integer>(); for(int i=1 ; i<=5 ; i++) list.add(i*5); System.out.println(“List is : “); for(Integer x : list) System.out.println(x); }} Display ArrayList element by element …
Iterator: Methods: Program to display ArrayList using Iterator: import java.util.*;class Code{ public static void main(String[] args) { List<Integer> list = new ArrayList<Integer>(); for(int i=1 ; i<=5 ; i++) list.add(i*5); System.out.println(“Display using Iterator :”); Iterator<Integer> itr = list.iterator(); while(itr.hasNext()) { Integer ele = itr.next(); System.out.println(ele); } }} When we use for/for-each/iterator? For-loop For-each loop Iterator Index …
ListIterator: Iterator List in Forward Direction using hasNext() and next() methods: List<Integer> list = new ArrayList<Integer>();for(int i=1 ; i<=5 ; i++){ list.add(i*5);}ListIterator<Integer> itr = list.listIterator();while(itr.hasNext()){ System.out.println(itr.next());} Iterator List in Backward Direction using hasPrevious() and previous() methods: List<Integer> list = new ArrayList<Integer>();for(int i=1 ; i<=5 ; i++){ list.add(i*5);}ListIterator<Integer> itr = list.listIterator(list.size());while(itr.hasPrevious()){ System.out.println(itr.previous());} Display list from specified …
List of Objects: Program to create and display List of Employees: Employee.java: class Employee{ int id; String name; double salary; Employee(int id, String name, double salary) { this.id = id; this.name = name; this.salary = salary; }} Main.java: import java.util.*;class Main{ public static void main(String[] args) { List<Employee> list = new ArrayList<Employee>(); Employee e1 = …