FIX: Protected Members Accessible to Subclass in Other Package

SYMPTOMS

The Java Language Compiler (jvc) incorrectly compiles code that violates field visibility rules according to the Java specification. If a sub- classed object (S) is derived from a base class (B) in another package that has a protected member variable (ld) and class S tries to access a member via a qualified name of Q.ld, access is permitted only if Q is S or a subclass of S. If Q is the base class of S, then access should not be permitted and an error should be generated. JVC compiles code that violates this field visibility rule without generating any warnings or errors.

// aProtectedPackage.myBaseClass
package aProtectedPackage;
public class myBaseClass {
   protected int myProtectedVariable;
}

// derivedClass
import aProtectedPackage.myBaseClass;
class derivedClass extends myBaseClass {
  void test(myBaseClass a) {
      this.myProtectedVariable=1;
      a.myProtectedVariable=0;  // this should generate an error
                                // according to 6.6.2, but JVC does not
                                // generate any warnings.
  }
}