#vulnerable code 
                                @Test
    public void testNoMsg() {
        final RegexFilter filter = RegexFilter.createFilter(Pattern.compile(".* test .*"), false, null, null);
        filter.start();
        assertTrue(filter.isStarted());
        assertSame(Filter.Result.DENY, filter.filter(null, Level.DEBUG, null, (String) null, (Throwable) null));
        assertSame(Filter.Result.DENY, filter.filter(null, Level.DEBUG, null, (Message) null, (Throwable) null));
        assertSame(Filter.Result.DENY, filter.filter(null, Level.DEBUG, null, null, (Object[]) null));

    } 
                            #location 4 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void testNoMsg() throws Exception {
        final RegexFilter filter = RegexFilter.createFilter(".* test .*", null, false, null, null);
        filter.start();
        assertTrue(filter.isStarted());
        assertSame(Filter.Result.DENY, filter.filter(null, Level.DEBUG, null, (String) null, (Throwable) null));
        assertSame(Filter.Result.DENY, filter.filter(null, Level.DEBUG, null, (Message) null, (Throwable) null));
        assertSame(Filter.Result.DENY, filter.filter(null, Level.DEBUG, null, null, (Object[]) null));
    }