only non static and non transient variables can be serialized.

if we want a variable to be instance variable,but the
variable is non serializable variable, then we declare that
variable as transient. here exactly we can make use of
transient.

static variables can also serialized but is a very 
cumbersome process. Transient keyword prefixing any 
variable states that the varible does serialized but its 
state i.e. value of the varible, does not serialize.

Both static & Transient are may not be serialized.

Static means one per class not one per object. Static 
variables are not saved and when an object is deserialized, 
it will have whatever static variable its class currently 
has. Don’t make serializable objects dependent on a 
dynamically-changing static variable. It might not be the 
same when the object comes back.

Transient variables are given a value of NULL for object 
references and defaults (0, false, etc) for primitives.