docs: public void fileExtend(int newFileSize) throws LogAllocationException
      {
          if (tc.isEntryEnabled())
              Tr.entry(tc, "fileExtend", new Object[] { new Integer(newFileSize), this });
  
          final int fileLength = _fileBuffer.capacity();
  
          if (fileLength < newFileSize)
          {
              try
              {
                  // Expand the file to the new size ensuring that its pointer
                  // remains in its current position.
                  int originalPosition = _fileBuffer.position();
  
                  // TODO
                  //        Tr.uncondEvent(tc, "Expanding log file to size of " + newFileSize + " bytes.");
                  Tr.event(tc, "Expanding log file to size of " + newFileSize + " bytes.");
  
                  if (_isMapped)
                  {
                      _fileBuffer = _fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, newFileSize);
                  }
                  else
                  {
                      // The file is not mapped.
                      // Allocate a new DirectByteBuffer, copy the old ByteBuffer into the new one,
                      // then write the new ByteBuffer to the FileChannel (automatically expanding it).
                      if (tc.isDebugEnabled())
                          Tr.debug(tc, "File is NOT mapped.  Allocating new DirectByteBuffer");
  
                      _fileBuffer.position(0);
  
                      final ByteBuffer newByteBuffer = ByteBuffer.allocateDirect(newFileSize);
                      newByteBuffer.put(_fileBuffer);
                      newByteBuffer.position(0);
  
                      _fileChannel.write(newByteBuffer, 0);
                      _fileBuffer = newByteBuffer;
                  }
  
                  _fileBuffer.position(originalPosition);
                  _fileSize = newFileSize;
              } catch (Exception exc)
              {
                  FFDCFilter.processException(exc, "com.ibm.ws.recoverylog.spi.LogFileHandle.fileExtend", "1266", this);
                  if (tc.isEntryEnabled())
                      Tr.event(tc, "Unable to extend file " + _fileName + " to " + newFileSize + " bytes");
                  if (tc.isEntryEnabled())
                      Tr.exit(tc, "fileExtend", "LogAllocationException");
                  throw new LogAllocationException(exc);
              }
          }
  
          if (tc.isEntryEnabled())
              Tr.exit(tc, "fileExtend");
      }