Microsoft KB Archive/177166

= FIX: Jvc.exe Gives Ambiguity Error on Overloaded Methods =

Article ID: 177166

Article Last Modified on 8/25/2005

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APPLIES TO


 * Microsoft Software Development Kit for Java 2.02
 * Microsoft Software Development Kit for Java 2.01
 * Microsoft Software Development Kit for Java 2.02
 * Microsoft Visual J++ 1.0 Standard Edition
 * Microsoft Visual J++ 1.1 Standard Edition

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This article was previously published under Q177166



SYMPTOMS
When using the new Java compiler provided in the Microsoft SDK for Java 2.0 (Jvc.exe version 1.02.4337), compiling code with overloaded methods whose parameters are various combinations of double and long types gives the following error: Ambig.java(14,5) : error J0079: Ambiguity between 'void Ambig.foo(double d, long l)' and 'void Ambig.foo(long l, double d)'



CAUSE
A bug in the Java Compiler (Jvc.exe) produces this error when the overloaded method that takes two doubles appears in the code first and directly before the method that takes two longs.



RESOLUTION
To work around this problem, either move the method that takes two doubles to any point in the class after the method that takes two longs, or move the method that takes two longs anywhere in the code after the other overloaded methods.



STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

This bug was corrected in Microsoft virtual machine contained in the SDK for Java 3.0 and later.



MORE INFORMATION
To reproduce the problem, compile the following code: public class Ambig {  public static void main(String args[]) {     Ambig b = new Ambig;

b.foo((long)1, (double)2); b.foo((double)1, (long)2); b.foo(1,2); b.foo(1.5,2.5);

// pause for user to press return try{System.in.read;}catch(Exception e){} }

public void foo(double d, double d2) {     System.out.println("Double = "+d+" Double2 = "+d2); }

public void foo(long l, long l2) {     System.out.println("Long = "+l+" Long2 = "+l2); }

public void foo(long l, double d)  { System.out.println("Long = "+l+" Double = "+d); }

public void foo(double d, long l)  { System.out.println("Double = "+d+" Long = "+l); } } You should see the following error: Ambig.java(14,5) : error J0079: Ambiguity between 'void Ambig.foo(double d, long l)' and 'void Ambig.foo(long l, double d)' To work around this problem, change the order of the overloaded methods to the following: public void foo(long l, long l2) {  System.out.println("Long = "+l+" Long2 = "+l2); }

public void foo(long l, double d) { System.out.println("Long = "+l+" Double = "+d); }

public void foo(double d, long l) { System.out.println("Double = "+d+" Long = "+l); }

public void foo(double d, double d2) {  System.out.println("Double = "+d+" Double2 = "+d2); }

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public void foo(double d, double d2) {  System.out.println("Double = "+d+" Double2 = "+d2); }

public void foo(long l, double d) { System.out.println("Long = "+l+" Double = "+d); }

public void foo(double d, long l) { System.out.println("Double = "+d+" Long = "+l); }

public void foo(long l, long l2) {  System.out.println("Long = "+l+" Long2 = "+l2); }

