diff --git a/gnu/packages/java.scm b/gnu/packages/java.scm
index f482c4c16d..567fb05f77 100644
--- a/gnu/packages/java.scm
+++ b/gnu/packages/java.scm
@@ -878,7 +878,14 @@ (define-public openjdk9
     (build-system gnu-build-system)
     (outputs '("out" "jdk" "doc"))
     (arguments
-     `(#:tests? #f; require jtreg
+     `(#:imported-modules
+       ((guix build ant-build-system)
+        ,@%gnu-build-system-modules)
+       #:modules
+       ((guix build utils)
+        (guix build gnu-build-system)
+        (ice-9 popen))
+       #:tests? #f; require jtreg
        #:make-flags '("all")
        #:disallowed-references ,(list (gexp-input icedtea-8)
                                       (gexp-input icedtea-8 "jdk"))
@@ -971,6 +978,80 @@ (define-public openjdk9
                 (find-files "."
                             "\\.c$|\\.h$"))
                #t)))
+           ;; By default OpenJDK only generates an empty keystore.  In order to
+           ;; be able to use certificates in Java programs we need to generate a
+           ;; keystore from a set of certificates.  For convenience we use the
+           ;; certificates from the nss-certs package.
+           (add-after 'install 'install-keystore
+             (lambda* (#:key inputs outputs #:allow-other-keys)
+               (use-modules (ice-9 rdelim))
+               (let* ((keystore  "cacerts")
+                      (certs-dir (search-input-directory inputs
+                                                         "etc/ssl/certs"))
+                      (keytool   (string-append (assoc-ref outputs "jdk")
+                                                "/bin/keytool")))
+                 (define (extract-cert file target)
+                   (call-with-input-file file
+                     (lambda (in)
+                       (call-with-output-file target
+                         (lambda (out)
+                           (let loop ((line (read-line in 'concat))
+                                      (copying? #f))
+                             (cond
+                              ((eof-object? line) #t)
+                              ((string-prefix? "-----BEGIN" line)
+                               (display line out)
+                               (loop (read-line in 'concat) #t))
+                              ((string-prefix? "-----END" line)
+                               (display line out)
+                               #t)
+                              (else
+                               (when copying? (display line out))
+                               (loop (read-line in 'concat) copying?)))))))))
+                 (define (import-cert cert)
+                   (format #t "Importing certificate ~a\n" (basename cert))
+                   (let ((temp "tmpcert"))
+                     (extract-cert cert temp)
+                     (let ((port (open-pipe* OPEN_WRITE keytool
+                                             "-import"
+                                             "-alias" (basename cert)
+                                             "-keystore" keystore
+                                             "-storepass" "changeit"
+                                             "-file" temp)))
+                       (display "yes\n" port)
+                       (when (not (zero? (status:exit-val (close-pipe port))))
+                         (format #t "failed to import ~a\n" cert)))
+                     (delete-file temp)))
+
+                 ;; This is necessary because the certificate directory contains
+                 ;; files with non-ASCII characters in their names.
+                 (setlocale LC_ALL "en_US.utf8")
+                 (setenv "LC_ALL" "en_US.utf8")
+
+                 (copy-file (string-append (assoc-ref outputs "out")
+                                           "/lib/security/cacerts")
+                            keystore)
+                 (chmod keystore #o644)
+                 (for-each import-cert (find-files certs-dir "\\.pem$"))
+                 (mkdir-p (string-append (assoc-ref outputs "out")
+                                         "/lib/security"))
+                 (mkdir-p (string-append (assoc-ref outputs "jdk")
+                                         "/lib/security"))
+
+                 ;; The cacerts files we are going to overwrite are chmod'ed as
+                 ;; read-only (444) in icedtea-8 (which derives from this
+                 ;; package).  We have to change this so we can overwrite them.
+                 (chmod (string-append (assoc-ref outputs "out")
+                                       "/lib/security/" keystore) #o644)
+                 (chmod (string-append (assoc-ref outputs "jdk")
+                                       "/lib/security/" keystore) #o644)
+
+                 (install-file keystore
+                               (string-append (assoc-ref outputs "out")
+                                              "/lib/security"))
+                 (install-file keystore
+                               (string-append (assoc-ref outputs "jdk")
+                                              "/lib/security")))))
          ;; Some of the libraries in the lib/ folder link to libjvm.so.
          ;; But that shared object is located in the server/ folder, so it
          ;; cannot be found.  This phase creates a symbolic link in the
@@ -1044,6 +1125,7 @@ (define-public openjdk9
        ("icedtea-8:jdk" ,icedtea-8 "jdk")
        ;; XXX: The build system fails with newer versions of GNU Make.
        ("make@4.2" ,gnu-make-4.2)
+       ("nss-certs" ,nss-certs)
        ("unzip" ,unzip)
        ("which" ,which)
        ("zip" ,zip)))
@@ -1126,6 +1208,7 @@ (define-public openjdk10
      `(("openjdk9" ,openjdk9)
        ("openjdk9:jdk" ,openjdk9 "jdk")
        ("make@4.2" ,gnu-make-4.2)
+       ("nss-certs" ,nss-certs)
        ("unzip" ,unzip)
        ("which" ,which)
        ("zip" ,zip)))))
@@ -1152,6 +1235,7 @@ (define-public openjdk11
       #:modules `((guix build gnu-build-system)
                   (guix build utils)
                   (ice-9 match)
+                  (ice-9 popen)
                   (srfi srfi-1)
                   (srfi srfi-26))
       #:disallowed-references (list (gexp-input openjdk10)
@@ -1394,6 +1478,7 @@ (define-public openjdk11
            openjdk10
            `(,openjdk10 "jdk")
            gnu-make-4.2
+           nss-certs
            pkg-config
            unzip
            which
