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equals() method of Object class in Java

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When you compare two object references using == operator, it evaluate to true only when both references refer to same object. public class Person { private Integer id; private String name; public Person(Integer id, String name) { this.id = id; this.name = name; } public static void main(String[] args) { Person p1 = new Person(1, "Prithvi"); Person p2 = p1; Person p3= new Person(1, "Prithvi"); System.out.println(p1==p2); System.out.println(p1==p3); } } Output: true false We have created 3 references of Person class. Object references p1 and p2 both refer to same object so comparison evaluate to true. Comparison of p1 and p3 evaluate to false, even though p3 has same contents as p1 but refer to different object so comparison returns false. Below image explains this - Objects p3 and p1 are meaningfully equal. We must have some way to see their content are same or not. But the question is, How will you compare two different object...
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Create your own LinkedList in Java

As a Java developer, we need to frequently use the collection framework. Have you ever tried to create your own any of the collection classes in Java? Here we go, we will see how to create our own LinkedList in Java. We will create a very simple class with add and get methods. Also, the LinkedList class of collection framework is doubly LinkedList but we will singly LinkedList. Line 36 to 42, we have created an inner class i.e Node with a generic type T. This class has 2 fields: item field is a generic type that will hold an actual value of LinkedList node. next field is a Node type that holds the address of the next node of the LinkedList. We have also defined a constructor to set value for the item field. In lines 4 and 5, we have created an instance variable of type Node in MyLinkedList class i.e. first and last. The field first will always hold the first node of the LinkedList and the field last will always hold the node of LinkedList. Now the question is, why...
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Data types and Literals in Java

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Data types Data types category:   Data types summary: Literals A constant value which can be assigned to variable is called "Literal". Integral Literals All possible value of Integral data type(byte, short, int and long) are called Integral Literals. Default Value: By default every Integral literal is int type. When you assign a value in long data byte and that value is more than 2147483647(Maximum value for int) then compiler will give you error. Ex: long a = 3000000000; Error: The literal 3000000000 of type int is out of range  Even though we have used long data type and value is also within range of long but still compiler gives error because every integral literal is int type. We can resolve this error by specifying long type explicitly. We can specify long type by suffixing l or L . Ex: long a = 3000000000L; Number System: Integral Literal can be represented as Decimal, Octal and Hexadecimal number systems. L...
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