IllegalArgumentException is thrown when getReaderForText()  is called on the plaintext flavor by passing a StringSelection transferable object. 

The getReaderForText() method internally checks if the object returned by the getTransferData(DataFlavor) called on a transferable object is an instance of String or
InputStream. But the StringSelection object returns a StringReader when the getTransferData(DataFlavor) is called by passing the plaintext flavor . And since
StringReader is not an instance of String or InputStream, the getReaderForText() method throws the IllrgalArgumentException. 

This exception is not thrown when a user defined transferable object is used. In the user defined transferable object the getTransferableObject(DataFlavor)
returns a ByteArrayInputStream object when called by passing a plaintext flavor. 
As the ByteArrayInputStream is an instance of InputStream, the getReaderForText() method doesn't throw the exception. 

In Windows:  When getReaderForText()  is called on the plaintext flavor by passing a StringSelection transferable object, the IllegalArgumentException is thrown. 

In Solaris:  When getReaderForText()  is called on the plaintext flavor by passing a StringSelection transferable object, the IllegalArgumentException is thrown. 

Testcase that reproduces this bug: 

1)getReaderExample.java  : This is a sample test case which contains a inner class(TextTransferable) that implements the Transferable interface. 

To Run the sample program : 

1) Run the getReaderExample.class 
2) Check the output at the terminal. 

Note: Run the test case using StringSelection object  as well as  TextTransferable object ( by commenting and uncommenting the necessary line in the
getReaderExample() constructor ). 
  

Suggestion: 

The getTransferData() of the StringSelection class should return an object which is an instance of  InputStream, instead of returning the StringReader object. 

Code taken from java.awt.datatransfer.StringSelection 

---------------------- 
--------------------- 
--------------------- 

public synchronized Object getTransferData(DataFlavor dataflavor) 
        throws UnsupportedFlavorException, IOException 
    { 
        if(dataflavor.equals(flavors[0])) 
            return data; 
        if(dataflavor.equals(flavors[1])) 
            return new StringReader(data); 

            /*****************************************************************/ 
            /** Instead of returning the StringReader, an ByteArrayInputStream can be returned **/ 

                byte[] textBytes = null; 
                String encoding = dataflavor.getParameter("charset"); 

                if (encoding == null) { 
                    textBytes = text.getBytes(); 
                } else { 
                    textBytes = text.getBytes(encoding); 
                } 

                ByteArrayInputStream sbis = new ByteArrayInputStream(textBytes); 
                return sbis; 

            /*****************************************************************/ 

        else 
            throw new UnsupportedFlavorException(dataflavor); 
    } 

###@###.### 1999-10-21