Program: 142408
Project: 142408
Buggy source:
@PostConstruct public void createComposite(Composite parentComposite){
  parent=parentComposite;
  grabSysOut();
  grabSysIn();
  parent.setLayout(new GridLayout(2,false));
  txtOutput=new Text(parent,SWT.READ_ONLY | SWT.MULTI | SWT.BORDER| SWT.WRAP);
  TextLengthLimiter tl=new TextLengthLimiter();
  txtOutput.addModifyListener(tl);
  txtOutput.setText("String_Node_Str" + System.lineSeparator());
  txtOutput.setEditable(false);
  txtOutput.setCursor(null);
  txtOutput.setLayoutData(new GridData(GridData.FILL_BOTH));
  final Slider slider=new Slider(parent,SWT.V_SCROLL);
  slider.setIncrement(1);
  slider.setPageIncrement(10);
  slider.setMaximum(maxLines);
  slider.setMinimum(0);
  slider.setLayoutData(new GridData(GridData.FILL_VERTICAL));
  SelectionListener sliderListener=new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      txtOutput.setText("String_Node_Str");
      for (int i=0; i < txtOutput.getBounds().height / txtOutput.getFont().getFontData()[0].getHeight(); i++) {
        consoleStrings.indexOf(consoleStrings.get(slider.getSelection() + i));
        appendToGuiFromList((consoleStrings.get(slider.getSelection() + i)));
      }
    }
  }
;
  slider.addSelectionListener(sliderListener);
  parent.setLayout(new GridLayout(2,false));
  txtInput=new Text(parent,SWT.BORDER);
  txtInput.setMessage("String_Node_Str");
  txtInput.addKeyListener(new KeyAdapter(){
    @Override public void keyReleased(    KeyEvent e){
      if ((e.character == SWT.CR) || (e.character == SWT.LF)) {
        String line=txtInput.getText();
        txtOutput.append(line + System.lineSeparator());
        inWriter.println(line);
        inWriter.flush();
        txtInput.setText("String_Node_Str");
      }
    }
  }
);
  txtInput.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
  PersoSim sim=new PersoSim();
  sim.loadPersonalization("String_Node_Str");
  Thread simThread=new Thread(sim);
  simThread.start();
  Thread uiBufferThread=new Thread(new Runnable(){
    @Override public void run(){
      while (true) {
        try {
          Thread.sleep(100);
        }
 catch (        InterruptedException e) {
        }
        appendToGui("String_Node_Str");
      }
    }
  }
);
  uiBufferThread.start();
}

Fixed version (ground truth):
@PostConstruct public void createComposite(Composite parentComposite){
  parent=parentComposite;
  grabSysOut();
  grabSysIn();
  parent.setLayout(new GridLayout(2,false));
  txtOutput=new Text(parent,SWT.READ_ONLY | SWT.MULTI | SWT.BORDER| SWT.WRAP);
  TextLengthLimiter tl=new TextLengthLimiter();
  txtOutput.addModifyListener(tl);
  txtOutput.setText("String_Node_Str" + System.lineSeparator());
  txtOutput.setEditable(false);
  txtOutput.setCursor(null);
  txtOutput.setLayoutData(new GridData(GridData.FILL_BOTH));
  consoleStrings.add("String_Node_Str");
  slider=new Slider(parent,SWT.V_SCROLL);
  slider.setIncrement(1);
  slider.setPageIncrement(10);
  slider.setMaximum(consoleStrings.size());
  slider.setMinimum(0);
  slider.setThumb(consoleStrings.size());
  slider.setLayoutData(new GridData(GridData.FILL_VERTICAL));
  SelectionListener sliderListener=new SelectionAdapter(){
    public void widgetSelected(    SelectionEvent e){
      txtOutput.setText("String_Node_Str");
      consoleStrings.indexOf(consoleStrings.get(slider.getSelection()));
      appendToGuiFromList((consoleStrings.get(slider.getSelection())));
      for (int i=0; i < 35; i++) {
        if (slider.getSelection() + i < consoleStrings.size()) {
          consoleStrings.indexOf(consoleStrings.get(slider.getSelection() + i));
          appendToGuiFromList((consoleStrings.get(slider.getSelection() + i)));
        }
 else         return;
      }
    }
  }
;
  try {
    slider.addSelectionListener(sliderListener);
  }
 catch (  IndexOutOfBoundsException IoobExc) {
  }
 finally {
    slider.setSelection(consoleStrings.size());
  }
  parent.setLayout(new GridLayout(2,false));
  txtInput=new Text(parent,SWT.BORDER);
  txtInput.setMessage("String_Node_Str");
  txtInput.addKeyListener(new KeyAdapter(){
    @Override public void keyReleased(    KeyEvent e){
      if ((e.character == SWT.CR) || (e.character == SWT.LF)) {
        String line=txtInput.getText();
        txtOutput.append(line + System.lineSeparator());
        inWriter.println(line);
        inWriter.flush();
        txtInput.setText("String_Node_Str");
      }
    }
  }
);
  txtInput.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
  PersoSim sim=new PersoSim();
  sim.loadPersonalization("String_Node_Str");
  Thread simThread=new Thread(sim);
  simThread.start();
  Thread uiBufferThread=new Thread(new Runnable(){
    @Override public void run(){
      while (true) {
        try {
          Thread.sleep(100);
        }
 catch (        InterruptedException e) {
        }
        appendToGui("String_Node_Str");
      }
    }
  }
);
  uiBufferThread.start();
}