Name: rmT116609 Date: 10/03/2001


C:\temp\jdk14test\src\main>c:\jdk1.4\bin\java -version
java version "1.4.0-beta2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta2-b77)
Java HotSpot(TM) Client VM (build 1.4.0-beta2-b77, mixed mode)


1. Executed a test program to demo MappedByteBuffer. It is taken from the Rot13
example from "Early Adopter J2SE 1.4" featured on JDC
http://developer.java.sun.com/developer/Books/EarlyJ2SE/

ran the program after a successful compile using

The command I used was c:\jdk1.4\bin\java nio.Rot13 README.txt

The README is the one distributed with the JDK .

2. The source to nio.Rot13.java

package nio;

import java.io.*;
import java.nio.channels.*;
import java.nio.*;

public class Rot13 {

    /** Creates new Rot13 */
    public Rot13() {
    }

    /**
    * @param args the command line arguments
    */
    public static void main (String args[]) {
        FileChannel in = null;
        
        if (args.length < 1) {
            System.err.println("No file specified");
            System.err.println("Usage: java Rot13 <file>");
            System.exit(1);
        }
        
        try {
            in = new RandomAccessFile(args[0], "rw").getChannel();
            MappedByteBuffer mbb = in.map(FileChannel.MAP_RO, 0L, (int) in.size());
            mbb.load();
            
            while (mbb.hasRemaining()) {
                byte c = mbb.get(mbb.position());
                
                if (('a' <= c) && (c <= 'z')) {
                    if (c < 'n') {
                        c += 13;
                    } else {
                        c -= 13;
                    }
                } else if (('A' <= c) && (c <= 'Z')) {
                    if (c < 'N') {
                        c += 13;
                    } else {
                        c -= 13;
                    }
                }
                
                mbb.put(c);
            }
            
            mbb.force();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException io) {}
        }
    }

}


3. the resulting log file:

Unexpected Signal : EXCEPTION_ACCESS_VIOLATION occurred at PC=0x6D3BBB22
Function=Unsafe_SetNativeByte+0x59
Library=c:\jdk1.4\jre\bin\client\jvm.dll

Current Java thread:
at sun.misc.Unsafe.putByte(Native Method)
at java.nio.DirectByteBuffer.put(DirectByteBuffer.java:186)
at nio.Rot13.main(Rot13.java:57)

Dynamic libraries:
0x00400000 - 0x00406000 c:\jdk1.4\bin\java.exe
0x77F80000 - 0x77FFA000 C:\WINNT\System32\ntdll.dll
0x77DB0000 - 0x77E0A000 C:\WINNT\system32\ADVAPI32.dll
0x77E80000 - 0x77F35000 C:\WINNT\system32\KERNEL32.DLL
0x77D40000 - 0x77DB0000 C:\WINNT\system32\RPCRT4.DLL
0x78000000 - 0x78046000 C:\WINNT\system32\MSVCRT.dll
0x6D330000 - 0x6D446000 c:\jdk1.4\jre\bin\client\jvm.dll
0x77E10000 - 0x77E74000 C:\WINNT\system32\USER32.dll
0x77F40000 - 0x77F7C000 C:\WINNT\system32\GDI32.DLL
0x77570000 - 0x775A0000 C:\WINNT\System32\WINMM.dll
0x6D1D0000 - 0x6D1D7000 c:\jdk1.4\jre\bin\hpi.dll
0x6D300000 - 0x6D30D000 c:\jdk1.4\jre\bin\verify.dll
0x6D210000 - 0x6D227000 c:\jdk1.4\jre\bin\java.dll
0x6D320000 - 0x6D32D000 c:\jdk1.4\jre\bin\zip.dll
0x6D2E0000 - 0x6D2E7000 C:\jdk1.4\jre\bin\nio.dll
0x75030000 - 0x75044000 C:\WINNT\System32\WS2_32.dll
0x75020000 - 0x75028000 C:\WINNT\System32\WS2HELP.DLL
0x77920000 - 0x77942000 C:\WINNT\system32\imagehlp.dll
0x72A00000 - 0x72A2D000 C:\WINNT\system32\DBGHELP.dll
0x690A0000 - 0x690AB000 C:\WINNT\System32\PSAPI.DLL

Local Time = Mon Oct 01 11:50:58 2001
Elapsed Time = 1
#
# HotSpot Virtual Machine Error : EXCEPTION_ACCESS_VIOLATION
# Error ID : 4F530E43505002D7
# Please report this error at
# http://java.sun.com/cgi-bin/bugreport.cgi
#
# Java VM: Java HotSpot(TM) Client VM (1.4.0-beta2-b77 mixed mode)
#


Interestingly I tried the same on a win98 m/c and it blows up as
but with a slightly different error log.

An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : EXCEPTION_ACCESS_VIOLATION occurred at PC=0x6D3BBB22
Function=[Unknown.]
Library=(N/A)

NOTE: We are unable to locate the function name symbol for the error
      just occurred. Please refer to release documentation for possible
      reason and solutions.


Current Java thread:
at sun.misc.Unsafe.putByte(Native Method)
at java.nio.DirectByteBuffer.put(DirectByteBuffer.java:186)
at nio.Rot13.main(Rot13.java:47)

Dynamic libraries:
0x7CC00000 - 0x7CC1D000 C:\WINDOWS\SYSTEM\IMAGEHLP.DLL

Local Time = Wed Oct 03 17:31:46 2001
Elapsed Time = 0
#
# The exception above was detected in native code outside the VM
#
# Java VM: Java HotSpot(TM) Client VM (1.4.0-beta2-b77 mixed mode)
#
(Review ID: 132886)
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