Integers

• Byte (8 bits)

-> Used to work with datastream from network or file. 
-> Also used when working with raw binary data that cant be stored in other types.

• Short (16 bits)

• Int (32 bits) - most widely used integer data type.

• long (64 bits)

Floating Numbers

• float (32 bits) - single precision floating numbers.

• double (64 bits) - doble precision floating numbers.

Character

• char (16 bytes ) - uses Unicode to represent many international languages.

** Boolean**

• true / false - these are non-numeric values in JAVA unlike C or C++ where these could be represented by non-zero and zero numbers respectively.

• Can take place when :

1. the two types are compatible.
2. destination type is larger than the source type.

• Explicit Conversion :

say we want to convert int to byte ,
byte b ; int a;
b = (byte) a;
here , modulo 256 (range of byte) value is assigned to b , if value of a is not in byte's range.

• Contiguous memory locations to store the homogenous values sequentially.
• Provides random access.
• int month[] = new int[12]; // here , all elements of the array are initialized to zero.
• int month[] = { 1,2,3,4,5,...12}; // auto-sizing