reference type vs primitive type

1// The value of primitive data types are directly stored in the memory.
2// For example if int a is initilized to 11, then 11 is directly stored
3// in the memory.
4int a = 11; // Primitive Type 
5
6// Reference types on the other hand are a reference to values in the
7// memory. For example Integer(11) creates a reference in the memory
8// whever the value 11 is stored and passes that memory reference/
9// (address) to the variable.
10Integer b = new Integer(11); // Reference Type 

1int a = 11; // Primitive Type 
2
3Integer b = new Integer(11); // Reference Type 
4

1+================+=========+===================================================================================+
2| Primitive type | Size    | Description                                                                       |
3+================+=========+===================================================================================+
4| byte           | 1 byte  | Stores whole numbers from -128 to 127                                             |
5+----------------+---------+-----------------------------------------------------------------------------------+
6| short          | 2 bytes | Stores whole numbers from -32,768 to 32,767                                       |
7+----------------+---------+-----------------------------------------------------------------------------------+
8| int            | 4 bytes | Stores whole numbers from -2,147,483,648 to 2,147,483,647                         |
9+----------------+---------+-----------------------------------------------------------------------------------+
10| long           | 8 bytes | Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
11+----------------+---------+-----------------------------------------------------------------------------------+
12| float          | 4 bytes | Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits           |
13+----------------+---------+-----------------------------------------------------------------------------------+
14| double         | 8 bytes | Stores fractional numbers. Sufficient for storing 15 decimal digits               |
15+----------------+---------+-----------------------------------------------------------------------------------+
16| char           | 2 bytes | Stores a single character/letter or ASCII values                                  |
17+----------------+---------+-----------------------------------------------------------------------------------+
18| boolean        | 1 bit   | Stores true or false values                                                       |
19+----------------+---------+-----------------------------------------------------------------------------------+