Wrapper Classes

Wrapper classes provide a way to use primitive data types (int, boolean, etc.) as objects.

Sometimes you must use wrapper classes, for example when working with Collection objects like ArrayList, where primitive types cannot be used.

Primitive vs Wrapper

Creating Wrapper Objects

Integer myInt = 5;
Double myDouble = 5.99;
Character myChar = 'A';

Autoboxing & Unboxing

• Autoboxing: Automatic conversion of primitive type to its corresponding object wrapper class.

  Character ch = 'a'; // Autoboxing
  

• Unboxing: Automatic conversion of wrapper class to primitive type.

  char c = ch; // Unboxing
  

Interactive Code

See how wrappers work.

Quiz

Next Steps

Programs don't always run smoothly. What happens when things go wrong? Module 7: Exception Handling.