Java Type Checking

• In a Java assignment statement, the type of the variable on the left hand side must be "wider" than the type of the expression on the right

• Suppose d is of type double, i is of type int, super is a class variable of type SuperClass, and sub is a class variable of type SubClass where SubClass extends SuperClass:

  • d = i; // OK
  • i = d; // NO
  • super = sub; // OK
  • sub = super; // NO