The attached program outputs UnknownCharacterException in Japanese locale.

REPRODUCE:

 (1) Compile the following program with -deprecation.

====>
import java.io.PrintWriter;
import java.net.*;
import java.io.*;

public class DecodeTests {

    final static String stringSetUTF =
        "\uD800\uDC00";

               // a string of surrogate pairs can be expressed as 4 bytes

    /* standalone interface */
    public static void main(String argv[]) {
        String encoded = URLEncoder.encode(stringSetUTF);
    }
}

<===


 (2) Launch "java DecodeTests" with LANG=ja,
     then you will see the below exception.
 
goedel[38]% java DecodeTests
Exception in thread "main" java.lang.Error: UnknownCharacterException thrown in substititution mode
        at sun.io.CharToByteConverter.convertAny(CharToByteConverter.java:160)
        at sun.nio.cs.StreamEncoder$ConverterSE.implWrite(StreamEncoder.java:210)
        at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:136)
        at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:124)
        at java.io.OutputStreamWriter.write(OutputStreamWriter.java:178)
        at java.net.URLEncoder.encode(URLEncoder.java:234)
        at java.net.URLEncoder.encode(URLEncoder.java:149)
        at DecodeTests.main(DecodeTests.java:15)
Caused by: sun.io.UnknownCharacterException
        at sun.io.CharToByteEUC_JP_Solaris.convert(CharToByteEUC_JP_Solaris.java:97)
        at sun.io.CharToByteConverter.convertAny(CharToByteConverter.java:139)
        ... 7 more

NOTE:

 1) Locale dependency

   If you change the locale to english, the test program seems to work well.

goedel[39]% setenv LANG C
goedel[40]% java DecodeTests
goedel[41]%


 2) JDK version dependency
    This issue occurs only in 1.4.2(_0X), not in 1.4.1 and 1.5b32.


CONFIGURATION:
  OS : SunOS goedel 5.8 Generic_108528-13 sun4u sparc SUNW,Ultra-60
  JDK : 1.4.2_02
    java version "1.4.2_02"
    Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_02-b03)
    Java HotSpot(TM) Client VM (build 1.4.2_02-b03, mixed mode)

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