Define Wrapper Classes in Java.

 In Java, wrapper classes are classes that provide a wrapper around a primitive data type. Wrapper classes are used to convert primitive data types to object types and vice versa.

Java has eight wrapper classes: Boolean, Byte, Character, Double, Float, Integer, Long, and Short. These wrapper classes correspond to the eight primitive data types in Java: boolean, byte, char, double, float, int, long, and short, respectively.

Here are some examples of how to use wrapper classes in Java:

// convert a primitive int to an Integer object int i = 10; Integer iWrapper = new Integer(i); // convert an Integer object to a primitive int int i2 = iWrapper.intValue(); // convert a primitive double to a Double object double d = 3.14; Double dWrapper = new Double(d); // convert a Double object to a primitive double double d2 = dWrapper.doubleValue();


In these examples, the Integer and Double wrapper classes are used to convert primitive data types (int and double) to object types (Integer and Double) and vice versa.

Wrapper classes are often used in collections that can only store objects (such as ArrayList or HashMap) and in situations where an object is required (such as when using method overloading).

I hope this helps! Let me know if you have any other questions.

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