• Static data members are those whose memory space is created only once, whenever the class is loaded in the main memory irrespective of no of objects are created.
• SDM are used to store common property of each object.
• Programmatically static data member declaration must be preceded by static keyword.
• Each and every static data member must be access with respective class name.
• Example:
  Class name.static data member name
• Static data member are also known as Class Level Data Members because they depends on class name and independent from object name.
• Syntax:
  static datatype x, y, z, .... ;
• Default value null or 0

public class Employee
{
static String cname;
public static void main (String args[])
	{
	System.out.println(cname);
	Employee.cname="HCL";
	System.out.println(Employee.cname);
	}
}
To Compile - javac employee.java
To Run - java Employee
Result - 	null
		HCL

• Instance data members are those whose memory space is created each and every time whenever an object is created.
• IDM are always meant for storing specific values.
• Each and every instance data member must be access with respective object name.
• Example: Objname.instance data member name
• Instance data members are also known as Object Level Data Members because they depend on object name and independent from class name.
• Syntax: datatype x, y, z, .... ;
• Default value null or 0

public class Employee
{
static 	String cname="HCL";
	String ename;
public static void main (String ...a)
	{
	Employee e1	= new Employee();
	Employee e2	= new Employee();
	e1.ename="Uves";
	System.out.println(cname);
	System.out.println(e1.ename);
	System.out.println(e2.ename);
	}
}
To Compile - javac employee.java
To Run - java Employee
Result - 	HCL
		Uves
		null