{"id":84570,"date":"2020-09-29T07:09:37","date_gmt":"2020-09-29T07:09:37","guid":{"rendered":"https:\/\/www.baeldung.com\/?p=87792"},"modified":"2020-09-29T07:09:37","modified_gmt":"2020-09-29T07:09:37","slug":"get-a-list-of-trusted-certificates-in-java","status":"publish","type":"post","link":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/2020\/09\/29\/get-a-list-of-trusted-certificates-in-java\/","title":{"rendered":"Get a List of Trusted Certificates in Java"},"content":{"rendered":"

<\/p>\n

1. Overview<\/h2>\n
<\/div>\n

In this quick tutorial, we’ll learn how to read a list of trusted certificates in Java through quick and practical examples.<\/p>\n

2. Loading the KeyStore<\/em><\/h2>\n
<\/div>\n

Java stores the trusted certificates in a special file named cacerts<\/em> that lives inside our Java installation folder.<\/p>\n

Let’s start by reading this file and loading it into the KeyStore<\/em><\/a>:<\/p>\n

private KeyStore loadKeyStore() {\r\n    String relativeCacertsPath = \"\/lib\/security\/cacerts\".replace(\"\/\", File.separator);\r\n    String filename = System.getProperty(\"java.home\") + relativeCacertsPath;\r\n    FileInputStream is = new FileInputStream(filename);\r\n    KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());\r\n    String password = \"changeit\";\r\n    keystore.load(is, password.toCharArray());\r\n    return keystore;\r\n}<\/code><\/pre>\n
The default password for this KeyStore<\/em> is “changeit”<\/em>, but it could be different if it was previously changed in our system.<\/strong><\/p>\n
Once loaded, the KeyStore<\/em> will hold our trusted certificates, and next, we’ll see how to read them.<\/p>\n
3. Reading Certificates From a Specified KeyStore<\/em><\/h2>\n
<\/div>\n
We’re going to use the PKIXParameters<\/a><\/em>\u00a0class, which takes a KeyStore<\/em> as a constructor parameter:<\/p>\n
@Test\r\npublic void whenLoadingCacertsKeyStore_thenCertificatesArePresent() {\r\n    KeyStore keyStore = loadKeyStore();\r\n    PKIXParameters params = new PKIXParameters(keyStore);\r\n    Set<TrustAnchor> trustAnchors = params.getTrustAnchors();\r\n    List<Certificate> certificates = trustAnchors.stream()\r\n      .map(TrustAnchor::getTrustedCert)\r\n      .collect(Collectors.toList());\r\n    assertFalse(certificates.isEmpty());\r\n}<\/code><\/pre>\n
The PKIXParameters<\/em> class is usually used for validating a certificate, but in our example, we simply used it to exact the certificates from our KeyStore<\/em>.<\/p>\n
When creating an instance of PKIXParametrs<\/em>, it builds a list of TrustAnchor<\/a><\/em>\u00a0that will contain the trusted certificates present in our KeyStore<\/em>.<\/p>\n
A TrustAnchor<\/em> instance simply represents a trusted certificate.<\/p>\n
4. Reading Certificates From Default KeyStore<\/em><\/h2>\n
<\/div>\n
We can also get a list of the trusted certificates present in our system by using the TrustManagerFactory<\/em>\u00a0class and initializing it without a KeyStore<\/em><\/strong>, which will use the default KeyStore<\/em>.<\/p>\n
If we don’t provide a KeyStore<\/em> explicitly, the same one from the previous chapter will be used by default:<\/p>\n
@Test\r\npublic void whenLoadingDefaultKeyStore_thenCertificatesArePresent() {\r\n    TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());\r\n    trustManagerFactory.init((KeyStore) null);\r\n    List<TrustManager> trustManagers = Arrays.asList(trustManagerFactory.getTrustManagers());\r\n    List<X509Certificate> certificates = trustManagers.stream()\r\n      .filter(X509TrustManager.class::isInstance)\r\n      .map(X509TrustManager.class::cast)\r\n      .map(trustManager -> Arrays.asList(trustManager.getAcceptedIssuers()))\r\n      .flatMap(Collection::stream)\r\n      .collect(Collectors.toList());\r\n    assertFalse(certificates.isEmpty());\r\n}<\/code><\/pre>\n
In the above example, we’ve used X509TrustManager<\/em>, which is a specialized TrustManager<\/em>\u00a0used to authenticate the remote part of an SSL connection<\/a>.<\/p>\n
5. Certificate Aliases<\/h2>\n
<\/div>\n
A certificate alias is simply a String<\/em> that uniquely identifies a certificate.<\/p>\n
Among the default certificates imported by Java, there’s also a well-known certificate issued by GoDaddy, a public Internet domain registrar, which we’ll use in our tests:<\/strong><\/p>\n
String GODADDY_CA_ALIAS = \"godaddyrootg2ca [jdk]\";<\/code><\/pre>\n
Let’s see how we can read all certificate aliases present in our KeyStore<\/em>:<\/p>\n
@Test\r\npublic void whenLoadingKeyStore_thenGoDaddyCALabelIsPresent() {\r\n    KeyStore keyStore = loadKeyStore();\r\n    Enumeration<String> aliasEnumeration = keyStore.aliases();\r\n    List<String> aliases = Collections.list(aliasEnumeration);\r\n    assertTrue(aliases.contains(GODADDY_CA_ALIAS));\r\n}<\/code><\/pre>\n
In the next example, we’ll see how we can retrieve a certificate by its alias:<\/p>\n
@Test\r\npublic void whenLoadingKeyStore_thenGoDaddyCertificateIsPresent() {\r\n    KeyStore keyStore = loadKeyStore();\r\n    Certificate goDaddyCertificate = keyStore.getCertificate(GODADDY_CA_ALIAS);\r\n    assertNotNull(goDaddyCertificate);\r\n}<\/code><\/pre>\n
6. Conclusion<\/h2>\n
<\/div>\n
In this quick article, we’ve looked at different ways of listing trusted certificates in Java through quick and practical examples.<\/strong><\/p>\n
As always, code snippets can be found over on GitHub<\/a>.<\/p>\n
The post Get a List of Trusted Certificates in Java<\/a> first appeared on Baeldung<\/a>.<\/p>\n
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<\/p>","protected":false},"excerpt":{"rendered":"
Learn how to read a list of trusted certificates in Java through quick and practical examples<\/p>\n
The post Get a List of Trusted Certificates in Java<\/a> first appeared on Baeldung<\/a>.<\/p>\n
<\/a> <\/a> <\/a> <\/a> <\/a> <\/a> <\/a> <\/a> <\/div>\n<\/div>","protected":false},"author":758,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"Get a List of Trusted Certificates in Java - ITTeacherITFreelance.hk","description":"Learn how to read a list of trusted certificates in Java through quick and practical examples The post Get a List of Trusted Certificates in Java first appeared"},"footnotes":""},"categories":[6],"tags":[],"_links":{"self":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/84570"}],"collection":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/users\/758"}],"replies":[{"embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/comments?post=84570"}],"version-history":[{"count":3,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/84570\/revisions"}],"predecessor-version":[{"id":85409,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/posts\/84570\/revisions\/85409"}],"wp:attachment":[{"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/media?parent=84570"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/categories?post=84570"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itteacheritfreelance.hk\/wordpress\/index.php\/wp-json\/wp\/v2\/tags?post=84570"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}