Note: Arrays, boxing, and unboxing are important concepts in Java related to handling data, especially primitive data types and their object counterparts. Let’s explore these concepts
Arrays
- Java object used to group primitives or objects.
- All components have the same type, e.g. int, String etc.
- Size cannot be changed after creation.
- Some methods:-
- public static int[] copyOf(int[] original, int newLength)
- public static int[] copyOfRange(int[] original,int from, int to)
Declaration
- You declare an array by specifying the data type, followed by square brackets [], and then the array name. For example, int[] numbers; declares an integer array.
Initialization
- Declaration with initialization: int[] numbers = {1, 2, 3, 4, 5};
- Separate initialization: int[] numbers = new int[5]; (creates an array of size 5)
Boxing & Unboxing
- Wrapper classes v/s primitive variables. .
- Conversion of primitive type to Wrapper type is called boxing.
- Conversion of Wrapper type to primitive type is called unboxing..
Varargs
- Pass any number of parameters in a method.
- E.g. public int checksum(int … vals)
- Helpful when one needs a flexibility of passing some unknown number of parameters, without creating an array.
format & printf methods
- Examples of using Varargs
- E.g public static String format(String formatString, Object… args)
