Binary compatibility implications of deleting method differ between 1.1 and JLS

Name: vsC45997 Date: 12/14/96


Let's consider a test checking the following assertion
[The section "13.4.5 Class Body and Member Declarations" of The Java Language
Specification contains the following]:

"Deleting a class member or constructor that is not declared private
may cause a linkage error if the member or constructor is used by a
pre-existing binary, even if the member was an instance method that was
overriding a superclass method. This is because, during resolution, the
linker looks only in the class that was identified at compile time."

The test below has been developed on the base of the example of the section
13.4.5 which follows the assertion cited above.

The test has been designed to demonstrate throwing "NoSuchMethodError"
when a deleted method "m" is used.
    try {
      String s = new Super().m();
      out.println (s);
    }
    ....

But JVM of JDK 1.1 uses the method "m" of the superclass Hyper
in run-time and "NoSuchFieldError" is not thrown.

The test consists of two files.

// FILE: binc02401.java
package javasoft.sqe.tests.lang.binc024.binc02401;
import java.io.PrintStream;

class Hyper {
  String m() { return "Hyper"; }
}

class Super extends Hyper {
  String m() { return "Super"; }
}

public class binc02401 {
  public static void main(String argv[])
  {
    System.exit(run(argv, System.out) + 95/*STATUS_TEMP*/);
  }
  public static int run(String argv[],PrintStream out) {
    try {
      String s = new Super().m();
      out.println (s);
    }
    catch (NoSuchMethodError e) {
      out.println (e);
      return 0/*STATUS_PASSED*/;
    }
    out.println ("failed");
    return 2/*STATUS_FAILED*/;
  }
}
    
    
// FILE: binc02401a.java
package javasoft.sqe.tests.lang.binc024.binc02401;

class Hyper {
  String m() { return "Hyper"; }
}

class Super extends Hyper { }


On JDK 1.1 we have the following output on this test:

Hyper
failed

The test passes successfully on JDK 1.0.2.

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