Q) What is the difference between equals() and == ?

Ans) == operator is used to compare the references of the objects. 
public bollean equals(Object o) is the method provided by the Object class. The default implementation uses == operator to compare two objects. But since the method can be overriden like for String class. equals() method can be used to compare the values of two objects.

String str1 = "MyName"; 
String str2 = "MyName";
String str3 = new String(str2);

if (str1 == str2) {
  System.out.println("Objects are equal")
}else{
  System.out.println("Objects are not equal")
}
if(str1.equals(str2)) {
  System.out.println("Objects are equal")
} else {
  System.out.println("Objects are not equal")
}

Output:
Objects are not equal
Objects are equal

String str2 = "MyName";
String str3 = str2;
if (str2 == str3) {
System.out.println("Objects are equal")
}else{
System.out.println("Objects are not equal")
}
if (str3.equals(str2)) {
  System.out.println("Objects are equal")
} else {
  System.out.println("Objects are not equal")
}

Output:
Objects are equal
Objects are equal