Single and Double byte Unicode character in DB through Java if DB has NLS_CHARACTERSET=WE8ISO8859P1

[shardul chand]

I am using the below Java code to set Latin-1 supplement character in the DB (NLS_CHARACTERSET = WE8ISO8859P1) but due to the DB not supporting these characters it is converting it into '?' or inverted '?'.
Is there a way to keep the the DB's NLS_CHARACTERSET as WE8ISO8859P1 and still support various languages (Single or Double Byte Unicode characters)?

StringBuffer query = new StringBuffer("begin update test_clob tc set " );
	      query.append(" tc.id = empty_clob() where tc.key1 = 1");
	      query.append(" returning tc.id into ? ; end;") ;

	      Connection con = null ;
	      CallableStatement cstm = null ;
	      try{
	    	  Class.forName("oracle.jdbc.driver.OracleDriver");
	    	  con = DriverManager.getConnection("Connection URL","user","pass");
	    	  con.setAutoCommit(false);
	    	  cstm = con.prepareCall(query.toString());
	    	  cstm.registerOutParameter(1,Types.CLOB);
	    	  cstm.execute();
	    	  Clob clob = (Clob)cstm.getClob(1);
	    	  Writer writer = null;
	          String encoding = "Cp1252";
	          if(encoding != null)
	              writer = new OutputStreamWriter(clob.setAsciiStream(0L), encoding);
	          else
	        	  writer = clob.setCharacterStream(0L);
              
              writer.write("<AltText>Test ä</AltText>");
              writer.flush();
              writer.close();
              con.commit();
              
              PreparedStatement pstmt = null;
              ResultSet rs = null;
              try {
                  pstmt = con.prepareStatement("select id from test_clob where key1 = 1");
                  rs = pstmt.executeQuery();
                  if(rs.next()) {
                      Clob tempC =  rs.getClob("id");
                      _getStringFromClob(tempC, "Cp1253");
                  }
              }catch(Exception e){
            	  e.printStackTrace();
              }
              cstm.close();
              con.close();
	      }catch(Exception e){
	    	  e.printStackTrace();
	      }
	}
	
	
	public void _getStringFromClob(Clob clob, String encoding){
     InputStream inputStream = null;
     ByteArrayOutputStream outputStream = null;
     try
     {
        int length = (int)clob.length();
        byte[] array = new byte[length];
        int inputStreamOffset = 0;
        inputStream = clob.getAsciiStream();
        outputStream = new ByteArrayOutputStream();

        // we have to loop because length is in characters not bytes
        while(true)
        {
           inputStreamOffset = inputStream.read(array, 0, length);
           if(inputStreamOffset < 1)
              break; 
           outputStream.write(array, 0, inputStreamOffset);
        }
        array = outputStream.toByteArray();
        System.out.println(new String(array, encoding));
     }
     catch(Exception e)
     {
        e.printStackTrace();
     }
     finally
     {
        try
        {
             if(inputStream != null)
                inputStream.close();
             if(outputStream != null)
                outputStream.close();
        }
        catch(IOException e)
        {
           e.printStackTrace();
        }
     }
  }

Please let me know if there is an solution to this. Thanks in advance.