[Demonstration 1]

[Buggy Method]
private String createAssignable() {
    StringBuilder sb = new StringBuilder();
    sb.append("assignable ");
    if (!assignedValues.keySet().isEmpty()) {
        for (Variable v : assignedValues.keySet()) {
            if (assignedValues.get(v).getStatus() != VariableValue.Status.known) {
                sb.append(v.toString());
                sb.append(", ");
            }
        }
        if (sb.lastIndexOf(", ") != -1) {
            return sb.substring(0, sb.lastIndexOf(", ")) + ";\n";
        }
    }
    sb.append("\\nothing;");
    return sb.toString();
}

[Buggy Hunk]
if (assignedValues.get(v).getStatus() != VariableValue.Status.known) {

[Patch]
if (assignedValues.get(v).getStatus() != VariableValue.Status.old) {

[Demonstration 3]

[Buggy Method]
public String createKey(String p, String ns, String local) {
    StringBuilder builder = new StringBuilder();
    String jns = getJSONNamespace(ns);
    if (jns != null && jns.length() != 0) {
        builder.append(jns).append('.');
    }
    return builder.append(local).toString();
}

[Buggy Hunk]
StringBuilder builder = new StringBuilder();

[Patch]
StringBuffer builder = new StringBuffer();