compile-time error for inherited abstract methods with throws conflict

Name: apC46001 Date: 12/19/96


JLS says [p. 167, 8.4.6.4 Inheriting Methods with the Same Signature]:

"It is possible for a class to inherit more than one method with the same signature.
Such a situation does not in itself cause a compile-time error.
There are then two possible cases:
   ...
If none of the inherited methods is not abstract, then the class is necessarily an
abstract class and is considered to inherit all the abstract methods.
A compile-time error occurs if, for any two such inherited methods, either they
have different return types or one has a return type and the other is void.
(The throws clauses do not cause errors in this case.)"
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
JDK 1.1 compiler produces unexpected error message for the correct java program.

> javac -d . clss17901.java

tests/lang/CLSS/clss179/clss17901/clss17901.java:14: Invalid exception class javasoft.sqe.tests.lang.clss179.clss17901.Ex2 in throws clause. The exception must be a subclass of an exception thrown by int m1() from interface javasoft.sqe.tests.lang.clss179.clss17901.clss17901_a.
int m1() throws Ex2;
^
tests/lang/CLSS/clss179/clss17901/clss17901.java:19: Invalid exception class javasoft.sqe.tests.lang.clss179.clss17901.Ex1 in throws clause. The exception must be a subclass of an exception thrown by int m1() from class javasoft.sqe.tests.lang.clss179.clss17901.clss17901_c.
public int m1() throws Ex1 {
^
tests/lang/CLSS/clss179/clss17901/clss17901.java:19: Invalid exception class javasoft.sqe.tests.lang.clss179.clss17901.Ex1 in throws clause. The exception must be a subclass of an exception thrown by int m1() from interface javasoft.sqe.tests.lang.clss179.clss17901.clss17901_b.
public int m1() throws Ex1 {
^
3 errors

--------------------------clss17901.java------------------------------
package javasoft.sqe.tests.lang.clss179.clss17901;


import java.io.PrintStream;

class Ex1 extends Exception {}
class Ex2 extends Exception {}
interface clss17901_a {
int m1() throws Ex1;
}
interface clss17901_b {
int m1() throws Ex2;
}
abstract class clss17901_c implements clss17901_b, clss17901_a {
}
class clss17901_d extends clss17901_c {
public int m1() throws Ex1 {
throw (new Ex1());
}
}

public class clss17901 {
  public static void main(String argv[])
  {
     System.exit(run(argv, System.out) + 95/*STATUS_TEMP*/);
  }
  public static int run(String argv[],PrintStream out) {
clss17901_d x = new clss17901_d();
try {
x.m1();
}
catch (Exception Ex1) {
return 0;
}
return 2;
  }
}


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