bablu:/home/sm123058/sudha/bugs/4042259/more 323 % java -version
java version "1.4.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta3-b83)
Java HotSpot(TM) Client VM (build 1.4.0-beta3-b83, mixed mode)
bablu:/home/sm123058/sudha/bugs/4042259/more 324 % more test.java
class A extends Exception {}
class B extends Exception {}
class C extends Exception {}

interface One {
    void method() throws A, C;
}

interface Two {
    void method() throws B, C;
}

abstract class conflict implements One, Two {


}
bablu:/home/sm123058/sudha/bugs/4042259/more 325 % javac test.java
bablu:/home/sm123058/sudha/bugs/4042259/more 326 % javap conflict
Exception in thread "main" java.lang.NullPointerException
        at sun.tools.java.Environment.error(Environment.java:857)
        at sun.tools.java.Environment.error(Environment.java:860)
        at sun.tools.java.ClassDefinition.collectOneClass(ClassDefinition.java:1409)
        at sun.tools.java.ClassDefinition.collectInheritedMethods(ClassDefinition.java:1504)
        at sun.tools.java.BinaryClass.basicCheck(BinaryClass.java:76)
        at sun.tools.java.ClassDeclaration.getClassDefinition(ClassDeclaration.java:133)
        at sun.tools.java.Environment.getClassDefinition(Environment.java:126)
        at sun.tools.javap.JavaP.displayResults(JavaP.java:196)
        at sun.tools.javap.JavaP.perform(JavaP.java:215)
        at sun.tools.javap.JavaP.entry(JavaP.java:236)
        at sun.tools.javap.JavaP.main(JavaP.java:223)
bablu:/home/sm123058/sudha/bugs/4042259/more 327 %

see bugid 4042259 public summary.