[Demonstration 1]

[Buggy Method]
@NonNull
private Condition combine(@NonNull final DefaultOperators operator, @NonNull final Condition condition) {
    final String newExpression = Utility.bracketString(expression) + operator.getSymbol() + Utility.bracketString(expression);
    final List<String> newArguments = new ArrayList<>(arguments);
    newArguments.addAll(condition.arguments);
    return new Condition(newExpression, newArguments);
}

[Buggy Hunk]
Utility.bracketString(expression);

[Patch]
Utility.bracketString(condition.expression);

[Demonstration 2]

[Buggy Method]
public static String evaluateReferenceValue(String functionName, int functionID, List<String> arguments, String defaultValue, boolean hasExplicitArguments) throws RendererException {
    String processedReferenceValue = "";
    switch(functionID) {
        case MM_TO_UPPER_CASE:
            if (hasExplicitArguments) {
                if (arguments.size() != 1)
                    throw new RendererException("function " + functionName + " expecting one argument, got " + arguments.size());
                processedReferenceValue = arguments.get(0).toUpperCase();
            } else
                processedReferenceValue = defaultValue.toUpperCase();
            break;
        case MM_TO_LOWER_CASE:
            if (hasExplicitArguments) {
                if (arguments.size() != 1)
                    throw new RendererException("function " + functionName + " expecting only one argument, got " + arguments.size());
                processedReferenceValue = arguments.get(0).toLowerCase();
            } else
                processedReferenceValue = defaultValue.toLowerCase();
            break;
        case MM_TRIM:
            if (hasExplicitArguments) {
                if (arguments.size() != 1)
                    throw new RendererException("function " + functionName + " expecting only one argument, got " + arguments.size());
                processedReferenceValue = arguments.get(0).trim();
            } else
                processedReferenceValue = defaultValue.trim();
            break;
        case MM_REVERSE:
            if (hasExplicitArguments) {
                if (arguments.size() != 1)
                    throw new RendererException("function " + functionName + " expecting only one argument, got " + arguments.size());
                processedReferenceValue = reverse(arguments.get(0));
            } else
                processedReferenceValue = reverse(defaultValue);
            break;
        case MM_CAPTURING:
            if (arguments.size() == 1) {
                processedReferenceValue = capture(defaultValue, arguments.get(0));
            } else if (arguments.size() == 2) {
                processedReferenceValue = capture(arguments.get(0), arguments.get(1));
            } else
                throw new RendererException("function " + functionName + " expecting one or two arguments, got " + arguments.size());
            break;
        case MM_PREPEND:
            if (arguments.size() == 1) {
                processedReferenceValue = arguments.get(0) + defaultValue;
            } else if (arguments.size() == 2) {
                processedReferenceValue = arguments.get(0) + arguments.get(1);
            } else
                throw new RendererException("function " + functionName + " expecting one or two arguments, got " + arguments.size());
            break;
        case MM_APPEND:
            if (arguments.size() == 1) {
                processedReferenceValue = defaultValue + arguments.get(0);
            } else if (arguments.size() == 2) {
                processedReferenceValue = arguments.get(0) + arguments.get(1);
            } else
                throw new RendererException("function " + functionName + " expecting one or two arguments, got " + arguments.size());
            break;
        case MM_REPLACE:
            if (arguments.size() == 2) {
                processedReferenceValue = defaultValue.replace(arguments.get(0), arguments.get(1));
            } else if (arguments.size() == 3) {
                processedReferenceValue = arguments.get(0).replace(arguments.get(1), arguments.get(2));
            } else
                throw new RendererException("function " + functionName + " expecting two or three arguments, got " + arguments.size());
            break;
        case MM_REPLACE_ALL:
            if (arguments.size() == 2) {
                processedReferenceValue = defaultValue.replaceAll(arguments.get(0), arguments.get(1));
            } else if (arguments.size() == 3) {
                processedReferenceValue = arguments.get(0).replaceAll(arguments.get(1), arguments.get(2));
            } else
                throw new RendererException("function " + functionName + " expecting two or three arguments, got " + arguments.size());
            break;
        case MM_REPLACE_FIRST:
            if (arguments.size() == 2) {
                processedReferenceValue = defaultValue.replaceFirst(arguments.get(0), arguments.get(1));
            } else if (arguments.size() == 3) {
                processedReferenceValue = arguments.get(0).replaceFirst(arguments.get(1), arguments.get(2));
            } else
                throw new RendererException("function " + functionName + " expecting two or three arguments, got " + arguments.size());
            break;
        default:
            throw new RendererException("unknown mapping function " + functionName);
    }
    return processedReferenceValue;
}

[Buggy Hunk]
processedReferenceValue = arguments.get(0) + arguments.get(1);

[Patch]
processedReferenceValue = defaultValue + arguments.get(0) + arguments.get(1);

[Demonstration 3]

[Buggy Method]
public void run() {
    try {
        TestETsts window = new TestETsts();
        window.frame.setVisible(true);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

[Buggy Hunk]
window.frame.setVisible(true);

[Patch]
window.frmBlackjack.setVisible(true);