Static Method Call - When we make a call to a static method (either directly from class or any object of that class), the Class object of that Class involves in that call. Every Class has only one Class object.
Non-static Call- When we call a non-static method (always from an object of that class), it works for that object only (which is of that class only). A class can have as many objects (if not restricted though some design patterns or lack of memory).
Now, lets come to Static and Non-static Synchronized method calls -
Static Synchronized Method Call - Whenever a thread accesses any synchronized static method, it acquires the lock on Class object of that class and hence no other static method can be accessed of that class.
Non-static Synchronized Method Call - As the non-static methods can be accessed through only objects of that class. So whenever, a thread enters any non-static synchronized method, it acquires the lock on the object through which the call has been made. Hence the other threads can still access the same or other non-static methods using other unlocked objects (free resources) of that class.