@Test
    public void testEmbeddedPDFs() throws Exception {
        List<Metadata> metadataList = getRecursiveMetadata("testPDFPackage.pdf");
        assertEquals(3, metadataList.size());
        assertEquals("true", metadataList.get(0).get(PDF.HAS_COLLECTION));
        assertContains("Adobe recommends using Adobe Reader ",
                metadataList.get(0).get(TikaCoreProperties.TIKA_CONTENT));
        assertContains("<p>PDF1", metadataList.get(1).get(TikaCoreProperties.TIKA_CONTENT));
        assertContains("<p>PDF2", metadataList.get(2).get(TikaCoreProperties.TIKA_CONTENT));
    }
PDFs can be "protected" with the default password. This means
they're encrypted (potentially both text and metadata),
but we can decrypt them easily.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-pdf-module/src/test/java/org/apache/tika/parser/pdf/PDFParserTest.java