Key Concepts

Review core concepts you need to learn to master this subject

Autoboxing Primitive Types

Unboxing Wrapper Classes

Integer and Double Wrapper Classes

Integer and Double Static Fields

Static Methods

Calling a Static Method

The Math Class

Autoboxing Primitive Types

// These are all examples of autoboxing
Double wrapper1 = 23.456;
Integer wrapper2 = 3;
Double wrapper3 = new Double(13.57);
Integer wrapper4 = new Integer(7);
Double wrapper5 = Double.valueOf(30.59);
Integer wrapper6 = Integer.valueOf(15);

Autoboxing is the automatic conversion that the Java compiler makes between primitive types and their corresponding object wrapper classes. This includes converting an int to an Integer and a double to a Double.