JavaScript String and Array Methods

String and Array Methods

• String methods belong to String objects.
• Array methods belong to the Arrays class.

ArrayList

• Follows typical object declaration syntax.
• Can add as many elements as needed, and the ArrayList grows accordingly.
• Very powerful, as the programmer is not responsible for basic behavior.

Auto-boxing and Auto-unboxing

• Auto-boxing and auto-unboxing allow primitive types to be treated as objects.
• Wrapper objects can be used like their wrapped primitives and provide advantages due to being objects, such as being members of ArrayLists.

BigInteger

• Grows arbitrarily large like a Python integer.
• Requires import java.math.*; to use.

Inheritance and Polymorphism

• Inheritance is used to create a new class based on an existing class.
• Inheritance is implemented using the "extends" keyword.

Upcasting

• Upcasting: a sub-class object can be treated as an instance of its super-class.
• This works because a sub-class can do everything its super-class can do.
• Liskov Substitution Principle: functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it.

Downcasting

• No direct mention of downcasting, but it is implied as the opposite of upcasting.

Overriding and Overloading

• Overriding: a sub-class provides a specific implementation for a method already defined in its super-class.
• Overloading: multiple methods with the same name but different parameters.
• @Override annotation is used to ensure that the method is intended to override a super-class method.

Overriding equals()

• When overriding equals(), ensure that the following hold true:
  • If a.equals(b), then b.equals(a) should be true.
  • If a.equals(b), and b.equals(c), then a.equals(c) should be true.
• A meaningful equals method is critical, as other classes rely on it, specifically methods add() and contains() from the Collection class.

This quiz covers the basics of string and array methods in JavaScript, including their syntax and usage.