Fix "Empty input" when loading SSL_CERT_FILE/SSL_CERT_DIR cert bundles.

api/src/main/java/io/minio/Http.java

@@ -37,6 +37,7 @@
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.security.cert.Certificate;
 import java.security.cert.CertificateException;
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
@@ -451,8 +452,7 @@ private static int setCertificateEntry(
       throws CertificateException, IOException, KeyStoreException {
     try (InputStream in = Files.newInputStream(file)) {
       int index = 0;
-      while (in.available() > 0) {
-        X509Certificate cert = (X509Certificate) cf.generateCertificate(in);
+      for (Certificate cert : cf.generateCertificates(in)) {
         ks.setCertificateEntry(namePrefix + (index++), cert);
       }
       return index;

api/src/test/java/io/minio/HttpExternalCertificatesTest.java

@@ -0,0 +1,85 @@
+/*
+ * MinIO Java SDK for Amazon S3 Compatible Cloud Storage,
+ * (C) 2026 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.minio;
+
+import java.io.File;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.util.Arrays;
+import java.util.Collection;
+import okhttp3.OkHttpClient;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+@RunWith(Parameterized.class)
+public class HttpExternalCertificatesTest {
+  private static final String CERT =
+      "-----BEGIN CERTIFICATE-----\n"
+          + "MIIC8TCCAdmgAwIBAgIIVQI5/aydlf4wDQYJKoZIhvcNAQEMBQAwJzElMCMGA1UE\n"
+          + "AxMcbWluaW8tamF2YS10ZXN0LWUwZWVmYWQwYjRiZTAeFw0yNjA2MDkwOTI4MDNa\n"
+          + "Fw0zNjA2MDYwOTI4MDNaMCcxJTAjBgNVBAMTHG1pbmlvLWphdmEtdGVzdC1lMGVl\n"
+          + "ZmFkMGI0YmUwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC2wswKet+8\n"
+          + "P0KEPycjP0cUeWtVuzwReMG4iMJxU80xg6rHzHW33tx89HEyhqBM0tAhnOlv8uyN\n"
+          + "dIlLQRKMNj2U82PW1DNfDqvahCqI1P5HEcqmHXYMXUIIuHQ42Vaq5Jw6LfUT5Xp3\n"
+          + "OskJuXsrqhJ/lI2tjO2IA6Ihq2qWH8HMK13usrRU8ercMi3v3l+NmE2v9cAYNjDn\n"
+          + "y+wE4TGIjxBnOcR7fSF6zcMydiu371FD53o3any47BGcjQrf11KuToMWCI6xRyox\n"
+          + "oRFif2heDNtPlm+sN7fLoz8RozLLN0GCT1+g3RfLDnbMOD/Zpl4JSSW+ZW43wrhH\n"
+          + "Kt+M32Wg1mvjAgMBAAGjITAfMB0GA1UdDgQWBBQc31QOSV+G44gzEaP0Nzki7+3j\n"
+          + "zDANBgkqhkiG9w0BAQwFAAOCAQEAbS1xk1KS7yflxFHcD0kdwaUi3y+zsD7JEqPo\n"
+          + "YtZsJB3YZF+7mCLcvpQpeOj/YjjS4Nfm+BTiBEm4iQ10XYJqq7Ld8+b37Lu0lUwq\n"
+          + "BEM05XdGqIy2ZElYLB4uwai/foAPqpASbtqfuF3k/r7Iv+vuLAcNDIZ95gpIbgyS\n"
+          + "1VezowSP4jSTlIISFhUlTJwD4sSA4FpdBs2JytjdQ+5bRbQPKC2lTRNUjDzIHWN0\n"
+          + "FcA+xu6MMlXe1EtVYSPPRoHnc/qBE0yEiyBglgqETxd1XUGuCZfCNSAICMafHtua\n"
+          + "DppeWJHfHv2CXNFva0iicwzYJ5kqoeJF8GAU3+QD0TMx59IfwA==\n"
+          + "-----END CERTIFICATE-----\n";
+
+  @Parameters(name = "{0}")
+  public static Collection<Object[]> bundles() {
+    return Arrays.asList(
+        new Object[][] {
+          {"single trailing newline", CERT},
+          {"no trailing newline", CERT.trim()},
+          {"trailing blank line", CERT + "\n"},
+          {"trailing whitespace", CERT + "   \n"},
+        });
+  }
+
+  @Parameter()
+  public String name;
+
+  @Parameter(1)
+  public String bundle;
+
+  @Test
+  public void loadsExternalCertificateBundle() throws Exception {
+    String path = writeBundle(bundle);
+    OkHttpClient client = Http.enableExternalCertificates(new OkHttpClient(), path, null);
+    Assert.assertNotNull(client);
+  }
+
+  private static String writeBundle(String content) throws Exception {
+    File file = File.createTempFile("minio-ca-bundle", ".pem");
+    file.deleteOnExit();
+    Files.write(file.toPath(), content.getBytes(StandardCharsets.UTF_8));
+    return file.getAbsolutePath();
+  }
+}