Program: 127062
Project: 127062
Buggy source:
@Override protected boolean checkFieldsValue(){
  String xmlXsdFilePathText=xmlXsdFilePath.getText();
  String outputFilePathText=outputFilePath.getText();
  boolean editable=xmlXsdFilePath.getEditable();
  StringBuffer msgError=new StringBuffer();
  if (creation && !noFileButton.getSelection() && !useFileButton.getSelection()) {
    msgError.append("String_Node_Str");
  }
  if (creation && editable && xmlXsdFilePathText == "String_Node_Str") {
    msgError.append("String_Node_Str");
  }
  if (!valid && creation) {
    if (xmlXsdFilePathText != null && !"String_Node_Str".equals(xmlXsdFilePathText)) {
      if (isContextMode()) {
        ContextType contextType=ConnectionContextHelper.getContextTypeForContextMode(connectionItem.getConnection());
        xmlXsdFilePathText=TalendQuoteUtils.removeQuotes(ConnectionContextHelper.getOriginalValue(contextType,xmlXsdFilePathText));
      }
      msgError.append(xmlXsdFilePathText + "String_Node_Str");
    }
  }
  if (isContextMode()) {
    ContextType contextType=ConnectionContextHelper.getContextTypeForContextMode(connectionItem.getConnection(),true);
    outputFilePathText=TalendQuoteUtils.removeQuotes(ConnectionContextHelper.getOriginalValue(contextType,outputFilePathText));
  }
  if (xmlXsdFilePathText != null && !xmlXsdFilePathText.equals("String_Node_Str")) {
    if (treePopulator.isValidFile(xmlXsdFilePathText)) {
      if (!XmlUtil.isXMLFile(xmlXsdFilePathText) && !XmlUtil.isXSDFile(xmlXsdFilePathText)) {
        msgError.append("String_Node_Str");
      }
    }
 else {
      msgError.append("String_Node_Str");
    }
  }
  if (outputFilePathText != null && !outputFilePathText.equals("String_Node_Str") && !XmlUtil.isXMLFile(outputFilePathText)) {
    msgError.append("String_Node_Str");
  }
  if ("String_Node_Str".equals(msgError.toString())) {
    updateStatus(IStatus.OK,null);
    return true;
  }
  updateStatus(IStatus.ERROR,msgError.toString());
  return false;
}

Fixed version (ground truth):
@Override protected boolean checkFieldsValue(){
  String xmlXsdFilePathText=xmlXsdFilePath.getText();
  String outputFilePathText=outputFilePath.getText();
  boolean editable=xmlXsdFilePath.getEditable();
  StringBuffer msgError=new StringBuffer();
  if (creation && !noFileButton.getSelection() && !useFileButton.getSelection()) {
    msgError.append("String_Node_Str");
  }
  if (creation && editable && xmlXsdFilePathText == "String_Node_Str") {
    msgError.append("String_Node_Str");
  }
  if (!valid && creation) {
    if (xmlXsdFilePathText != null && !"String_Node_Str".equals(xmlXsdFilePathText)) {
      if (isContextMode()) {
        ContextType contextType=ConnectionContextHelper.getContextTypeForContextMode(connectionItem.getConnection());
        xmlXsdFilePathText=TalendQuoteUtils.removeQuotes(ConnectionContextHelper.getOriginalValue(contextType,xmlXsdFilePathText));
      }
      msgError.append(xmlXsdFilePathText + "String_Node_Str");
    }
  }
  if (isContextMode()) {
    ContextType contextType=ConnectionContextHelper.getContextTypeForContextMode(connectionItem.getConnection(),true);
    outputFilePathText=TalendQuoteUtils.removeQuotes(ConnectionContextHelper.getOriginalValue(contextType,outputFilePathText));
  }
  if (xmlXsdFilePathText != null && !xmlXsdFilePathText.equals("String_Node_Str") && (xsdPathChanged || creation)) {
    if (treePopulator.isValidFile(xmlXsdFilePathText)) {
      if (!XmlUtil.isXMLFile(xmlXsdFilePathText) && !XmlUtil.isXSDFile(xmlXsdFilePathText)) {
        msgError.append("String_Node_Str");
      }
    }
 else {
      msgError.append("String_Node_Str");
    }
  }
  if (outputFilePathText != null && !outputFilePathText.equals("String_Node_Str") && !XmlUtil.isXMLFile(outputFilePathText)) {
    msgError.append("String_Node_Str");
  }
  if ("String_Node_Str".equals(msgError.toString())) {
    updateStatus(IStatus.OK,null);
    return true;
  }
  updateStatus(IStatus.ERROR,msgError.toString());
  return false;
}