#vulnerable code 
                                @Test
    public void testDecodePadOnlyChunked() {
        assertEquals(0, Base64.decodeBase64("====\n".getBytes(Charsets.UTF_8)).length);
        assertEquals("", new String(Base64.decodeBase64("====\n".getBytes(Charsets.UTF_8))));
        // Test truncated padding
        assertEquals(0, Base64.decodeBase64("===\n".getBytes(Charsets.UTF_8)).length);
        assertEquals(0, Base64.decodeBase64("==\n".getBytes(Charsets.UTF_8)).length);
        assertEquals(0, Base64.decodeBase64("=\n".getBytes(Charsets.UTF_8)).length);
        assertEquals(0, Base64.decodeBase64("\n".getBytes(Charsets.UTF_8)).length);
    } 
                            #location 3 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void testDecodePadOnlyChunked() {
        assertEquals(0, Base64.decodeBase64("====\n".getBytes(CHARSET_UTF8)).length);
        assertEquals("", new String(Base64.decodeBase64("====\n".getBytes(CHARSET_UTF8))));
        // Test truncated padding
        assertEquals(0, Base64.decodeBase64("===\n".getBytes(CHARSET_UTF8)).length);
        assertEquals(0, Base64.decodeBase64("==\n".getBytes(CHARSET_UTF8)).length);
        assertEquals(0, Base64.decodeBase64("=\n".getBytes(CHARSET_UTF8)).length);
        assertEquals(0, Base64.decodeBase64("\n".getBytes(CHARSET_UTF8)).length);
    }