--- a/src/java.base/share/classes/java/security/KeyStore.java	Fri Jun 12 14:33:20 2020 -0700
+++ b/src/java.base/share/classes/java/security/KeyStore.java	Sat Jun 13 17:49:15 2020 +0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1762,35 +1762,33 @@
             dataStream.mark(Integer.MAX_VALUE);
 
             // Detect the keystore type
-            for (String type : Security.getAlgorithms("KeyStore")) {
-                Object[] objs = null;
-
-                try {
-                    objs = Security.getImpl(type, "KeyStore", (String)null);
-
-                    KeyStoreSpi impl = (KeyStoreSpi)objs[0];
-                    if (impl.engineProbe(dataStream)) {
-
-                        if (kdebug != null) {
-                            kdebug.println(type + " keystore detected: " +
-                                file);
+            for (Provider p : Security.getProviders()) {
+                for (Provider.Service s : p.getServices()) {
+                    if (s.getType().equals("KeyStore")) {
+                        try {
+                            KeyStoreSpi impl = (KeyStoreSpi) s.newInstance(null);
+                            if (impl.engineProbe(dataStream)) {
+                                if (kdebug != null) {
+                                    kdebug.println(s.getAlgorithm()
+                                            + " keystore detected: " + file);
+                                }
+                                keystore = new KeyStore(impl, p, s.getAlgorithm());
+                                break;
+                            }
+                        } catch (NoSuchAlgorithmException e) {
+                            // ignore
+                            if (kdebug != null) {
+                                kdebug.println("not found - " + e);
+                            }
+                        } catch (IOException e) {
+                            // ignore
+                            if (kdebug != null) {
+                                kdebug.println("I/O error in " + file + " - " + e);
+                            }
                         }
-
-                        keystore = new KeyStore(impl, (Provider)objs[1], type);
-                        break;
-                    }
-                } catch (NoSuchAlgorithmException | NoSuchProviderException e) {
-                    // ignore
-                    if (kdebug != null) {
-                        kdebug.println(type + " not found - " + e);
-                    }
-                } catch (IOException e) {
-                    // ignore
-                    if (kdebug != null) {
-                        kdebug.println("I/O error in " + file + " - " + e);
+                        dataStream.reset(); // prepare the stream for the next probe
                     }
                 }
-                dataStream.reset(); // prepare the stream for the next probe
             }
 
             // Load the keystore data

--- a/src/java.base/share/classes/sun/security/provider/JavaKeyStore.java	Fri Jun 12 14:33:20 2020 -0700
+++ b/src/java.base/share/classes/sun/security/provider/JavaKeyStore.java	Sat Jun 13 17:49:15 2020 +0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -75,6 +75,22 @@
         public DualFormatJKS() {
             super("JKS", JKS.class, "PKCS12", PKCS12KeyStore.class);
         }
+
+        /**
+         * Probe the first few bytes of the keystore data stream for a valid
+         * JKS keystore encoding.
+         */
+        @Override
+        public boolean engineProbe(InputStream stream) throws IOException {
+            DataInputStream dataStream;
+            if (stream instanceof DataInputStream) {
+                dataStream = (DataInputStream)stream;
+            } else {
+                dataStream = new DataInputStream(stream);
+            }
+
+            return MAGIC == dataStream.readInt();
+        }
     }
 
     private static final Debug debug = Debug.getInstance("keystore");
@@ -828,20 +844,4 @@
         }
         return passwdBytes;
     }
-
-    /**
-     * Probe the first few bytes of the keystore data stream for a valid
-     * JKS keystore encoding.
-     */
-    @Override
-    public boolean engineProbe(InputStream stream) throws IOException {
-        DataInputStream dataStream;
-        if (stream instanceof DataInputStream) {
-            dataStream = (DataInputStream)stream;
-        } else {
-            dataStream = new DataInputStream(stream);
-        }
-
-        return MAGIC == dataStream.readInt();
-    }
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/security/KeyStore/OneProbeOneNot.java	Sat Jun 13 17:49:15 2020 +0800
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8245679
+ * @summary KeyStore cannot probe PKCS12 keystore if BouncyCastle is the top security provider
+ * @run main/othervm OneProbeOneNot
+ */
+
+import java.io.File;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.*;
+import java.security.cert.Certificate;
+import java.util.Date;
+import java.util.Enumeration;
+
+public class OneProbeOneNot {
+    public static final void main(String[] args) throws Exception {
+        Files.write(Path.of("ks"), "".getBytes());
+        // 1st provider do not support probe
+        Security.insertProviderAt(new P1(), 1);
+        // 2nd provider support probe
+        Security.insertProviderAt(new P2(), 2);
+        KeyStore ks = KeyStore.getInstance(new File("ks"), (char[])null);
+        System.out.println(ks.getProvider().getName());
+        System.out.println(ks.getType());
+    }
+
+    public static class P1 extends Provider {
+        public P1() {
+            super("P1", "P1", "P1");
+            putService(new Service(this, "KeyStore", "Oops",
+                    K1.class.getName(), null, null));
+        }
+    }
+    public static class P2 extends Provider {
+        public P2() {
+            super("P2", "P2", "P2");
+            putService(new Service(this, "KeyStore", "Oops",
+                    K2.class.getName(), null, null));
+        }
+    }
+
+    public static class K1 extends KeyStoreSpi {
+        public Key engineGetKey(String a, char[] p) { return null; }
+        public Certificate[] engineGetCertificateChain(String a) { return null; }
+        public Certificate engineGetCertificate(String a) { return null; }
+        public Date engineGetCreationDate(String a) { return null; }
+        public void engineSetKeyEntry(String a, Key k, char[] p, Certificate[] c) { }
+        public void engineSetKeyEntry(String a, byte[] k, Certificate[] c) { }
+        public void engineSetCertificateEntry(String a, Certificate c) { }
+        public void engineDeleteEntry(String a) { }
+        public Enumeration<String> engineAliases() { return null; }
+        public boolean engineContainsAlias(String a) { return false; }
+        public int engineSize() { return 0; }
+        public boolean engineIsKeyEntry(String a) { return false; }
+        public boolean engineIsCertificateEntry(String a) { return false; }
+        public String engineGetCertificateAlias(Certificate c) { return null; }
+        public void engineStore(OutputStream stream, char[] password) { }
+        public void engineLoad(InputStream stream, char[] password) { }
+    }
+
+    public static class K2 extends K1 {
+        public boolean engineProbe(InputStream s) {
+            return true;
+        }
+    }
+}