#vulnerable code 
                                public static Map<String, Pair<Method>> getPropertySetterGetterMethods(
            Class<? extends Object> theClass ) {

        Method[] methods = theClass.getMethods ( );

        Map<String, Pair<Method>> methodMap = new LinkedHashMap<> ( methods.length );
        List<Method> getterMethodList = new ArrayList<> ( methods.length );

        for ( int index = 0; index < methods.length; index++ ) {
            Method method = methods[index];
            String name = method.getName ( );

            if ( method.getParameterTypes ( ).length == 1
                    && method.getReturnType ( ) == void.class
                    && name.startsWith ( "set" ) ) {
                Pair<Method> pair = new Pair<Method> ( );
                pair.setFirst ( method );
                String propertyName = slc ( name, 3 );

                propertyName = lower ( slc ( propertyName, 0, 1 ) ) + slc ( propertyName, 1 );
                methodMap.put ( propertyName, pair );
            }

            if ( method.getParameterTypes ( ).length > 0
                    || method.getReturnType ( ) == void.class
                    || !( name.startsWith ( "get" ) || name.startsWith ( "is" ) )
                    || name.equals ( "getClass" ) ) {
                continue;
            }
            getterMethodList.add ( method );
        }

        for ( Method method : getterMethodList ) {
            String name = method.getName ( );
            String propertyName = null;
            if ( name.startsWith ( "is" ) ) {
                propertyName = slc ( name, 2 );
            } else if ( name.startsWith ( "get" ) ) {
                propertyName = slc ( name, 3 );
            }

            propertyName = lower ( slc ( propertyName, 0, 1 ) ) + slc ( propertyName, 1 );

            Pair<Method> pair = methodMap.get ( propertyName );
            if ( pair == null ) {
                pair = new Pair<Method> ( );
                methodMap.put ( propertyName, pair );
            }
            pair.setSecond ( method );

        }
        return methodMap;
    } 
                            #location 20 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public static Map<String, Pair<Method>> getPropertySetterGetterMethods(
            Class<? extends Object> theClass ) {

        Method[] methods = theClass.getMethods ( );

        Map<String, Pair<Method>> methodMap = new LinkedHashMap<> ( methods.length );
        List<Method> getterMethodList = new ArrayList<> ( methods.length );

        for ( int index = 0; index < methods.length; index++ ) {
            Method method = methods[index];
            String name = method.getName ( );

            if ( method.getParameterTypes ( ).length == 1
                    && method.getReturnType ( ) == void.class
                    && name.startsWith ( "set" ) ) {
                Pair<Method> pair = new Pair<Method> ( );
                pair.setFirst ( method );
                String propertyName = slc ( name, 3 );

                propertyName = lower ( slc ( propertyName, 0, 1 ) ) + slc ( propertyName, 1 );
                methodMap.put ( propertyName, pair );
            }

            if ( method.getParameterTypes ( ).length > 0
                    || method.getReturnType ( ) == void.class
                    || !( name.startsWith ( "get" ) || name.startsWith ( "is" ) )
                    || name.equals ( "getClass" ) ) {
                continue;
            }
            getterMethodList.add ( method );
        }

        for ( Method method : getterMethodList ) {
            String name = method.getName ( );
            String propertyName = null;
            if ( name.startsWith ( "is" ) ) {
                propertyName = name.substring ( 2 );
            } else if ( name.startsWith ( "get" ) ) {
                propertyName = name.substring ( 3 );
            }

            propertyName = lower ( propertyName.substring (  0, 1 ))  +  propertyName.substring (  1 ) ;

            Pair<Method> pair = methodMap.get ( propertyName );
            if ( pair == null ) {
                pair = new Pair<> ( );
                methodMap.put ( propertyName, pair );
            }
            pair.setSecond ( method );

        }
        return methodMap;
    }