Color outputColor = new Color(Color.BLUE.getRGB());
Color errorColor = new Color(Color.RED.getRGB());
...
outputAtr = new SimpleAttributeSet();
errorAtr = new SimpleAttributeSet();
StyleConstants.setForeground(outputAtr, outputColor);
StyleConstants.setForeground(errorAtr, errorColor);
...
jOutputDoc = jOutputPane.getStyledDocument();
...
// Ausgabe am Ende des Dokuments
jOutputDoc.insertString(jOutputDoc.getLength(),s,outputAtr);
jOutputPane.setCaretPosition(jOutputDoc.getLength());
// Fehlerausgabe am Ende des Dokuments
jOutputDoc.insertString(jInputDoc.getLength(),s,errorAtr);
jOutputPane.setCaretPosition(jOutputDoc.getLength());