The object type conversion java

Transition between the basic data types:

• Automatic conversion: smaller data types can be automatically converted to uppercase data type;
• Cast: large data can be converted into small data types Type: float = (float) 32.0;

public class Person extends Object{}

public class Student extends Person{}

Mandatory for java objects into shape:

• May be performed from subclass to superclass automatic type conversions;
  Student Student new new S = ();
  the Person P = S;
  String A = "Hello";
  Object obj = A;
• Can not be converted into the parent subclass; unless the reference to the parent class is that subclass, namely:
  the Person new new Student P = ();
  Student S = (Student) P;
  otherwise:
  Object OBJ1 = "World";
  String = A1 (String) obj1;
• No inheritance relationship between type conversion reference is illegal;: