eugenp · theangrydev · Nov 5, 2025 · Nov 3, 2025
diff --git a/libraries-io/pom.xml b/libraries-io/pom.xml
@@ -63,6 +63,19 @@
             <artifactId>jakarta.mail-api</artifactId>
             <version>${jakarta-mail.version}</version>
         </dependency>
+
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>testcontainers</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>testcontainers-junit-jupiter</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -80,15 +93,16 @@
 
     <properties>
         <!-- sftp -->
-        <jsch.version>0.2.16</jsch.version>
+        <jsch.version>2.27.5</jsch.version>
         <sshj.version>0.38.0</sshj.version>
-        <commons-vfs2.version>2.9.0</commons-vfs2.version>
+        <commons-vfs2.version>2.10.0</commons-vfs2.version>
         <zip4j.version>2.11.5</zip4j.version>
         <opencsv.version>5.9</opencsv.version>
         <spring.version>6.1.4</spring.version>
         <simplejavamail.version>8.7.0</simplejavamail.version>
         <jakarta-mail.version>2.1.3</jakarta-mail.version>
         <imap.version>2.0.1</imap.version>
+        <testcontainers.version>2.0.1</testcontainers.version>
     </properties>
 
 </project>
diff --git a/libraries-io/src/test/java/com/baeldung/java/io/jsch/BaseUserInfo.java b/libraries-io/src/test/java/com/baeldung/java/io/jsch/BaseUserInfo.java
@@ -0,0 +1,35 @@
+package com.baeldung.java.io.jsch;
+
+import com.jcraft.jsch.UserInfo;
+
+public class BaseUserInfo implements UserInfo {
+    @Override
+    public String getPassphrase() {
+        return null;
+    }
+
+    @Override
+    public String getPassword() {
+        return null;
+    }
+
+    @Override
+    public boolean promptPassword(String message) {
+        return false;
+    }
+
+    @Override
+    public boolean promptPassphrase(String message) {
+        return false;
+    }
+
+    @Override
+    public boolean promptYesNo(String message) {
+        return false;
+    }
+
+    @Override
+    public void showMessage(String message) {
+
+    }
+}
diff --git a/libraries-io/src/test/java/com/baeldung/java/io/jsch/ConnectIntegrationTest.java b/libraries-io/src/test/java/com/baeldung/java/io/jsch/ConnectIntegrationTest.java
@@ -0,0 +1,176 @@
+package com.baeldung.java.io.jsch;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.nio.file.Paths;
+
+import org.junit.jupiter.api.Test;
+import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+import org.testcontainers.utility.MountableFile;
+
+import com.jcraft.jsch.JSch;
+import com.jcraft.jsch.JSchException;
+import com.jcraft.jsch.JSchUnknownHostKeyException;
+import com.jcraft.jsch.Session;
+
+@Testcontainers
+class ConnectIntegrationTest {
+    private static final int SFTP_PORT = 22;
+
+    private static final String USERNAME = "baeldung";
+    private static final String PASSWORD = "test";
+    private static final String DIRECTORY = "upload";
+
+    // atmoz/sftp is a Docker container for an SFTP server that can easily support password and key authentication.
+    @Container
+    public static GenericContainer<?> sftpContainer = new GenericContainer<>("atmoz/sftp:latest")
+        .withExposedPorts(SFTP_PORT)
+        .withCommand(USERNAME + ":" + PASSWORD + ":::" + DIRECTORY)
+        .withCopyFileToContainer(
+            MountableFile.forHostPath(Paths.get("src/test/resources/com/baeldung/java/io/jsch/nopassphrase/id_rsa.pub")),
+            "/home/" + USERNAME + "/.ssh/keys/id_rsa.pub"
+        )
+        .withCopyFileToContainer(
+            MountableFile.forHostPath(Paths.get("src/test/resources/com/baeldung/java/io/jsch/passphrase/id_rsa.pub")),
+            "/home/" + USERNAME + "/.ssh/keys/id_rsa2.pub"
+        );
+
+    @Test
+    void whenTheHostKeyIsUnknown_thenTheConnectionFails() throws Exception {
+        JSch jSch = new JSch();
+
+        Session session = jSch.getSession(USERNAME, sftpContainer.getHost(), sftpContainer.getMappedPort(SFTP_PORT));
+
+        session.setUserInfo(new BaseUserInfo() {});
+
+        assertThrows(JSchUnknownHostKeyException.class, () -> session.connect());
+    }
+
+    @Test
+    void whenNoAuthenticationIsProvided_thenTheConnectionFails() throws Exception {
+        JSch jSch = new JSch();
+
+        Session session = jSch.getSession(USERNAME, sftpContainer.getHost(), sftpContainer.getMappedPort(SFTP_PORT));
+
+        session.setUserInfo(new BaseUserInfo() {
+
+            @Override
+            public boolean promptYesNo(String message) {
+                if (message.startsWith("The authenticity of host")) {
+                    return true;
+                }
+
+                return false;
+            }
+        });
+
+        JSchException exception = assertThrows(JSchException.class, () -> session.connect());
+        assertEquals("Auth cancel for methods 'publickey,password,keyboard-interactive'", exception.getMessage());
+    }
+
+    @Test
+    void whenPasswordAuthIsProvided_thenTheConnectionSucceeds() throws Exception {
+        JSch jSch = new JSch();
+
+        Session session = jSch.getSession(USERNAME, sftpContainer.getHost(), sftpContainer.getMappedPort(SFTP_PORT));
+
+        session.setUserInfo(new BaseUserInfo() {
+            @Override
+            public String getPassword() {
+                return PASSWORD;
+            }
+
+            @Override
+            public boolean promptPassword(String message) {
+                return true;
+            }
+
+            @Override
+            public boolean promptYesNo(String message) {
+                if (message.startsWith("The authenticity of host")) {
+                    return true;
+                }
+
+                return false;
+            }
+        });
+
+        session.connect();
+    }
+
+    @Test
+    void givenAnOpenSSHKey_whenKeyAuthIsProvided_thenTheConnectionSucceeds() throws Exception {
+        JSch jSch = new JSch();
+        jSch.addIdentity("src/test/resources/com/baeldung/java/io/jsch/nopassphrase/id_rsa");
+
+        Session session = jSch.getSession(USERNAME, sftpContainer.getHost(), sftpContainer.getMappedPort(SFTP_PORT));
+
+        session.setUserInfo(new BaseUserInfo() {
+            @Override
+            public boolean promptYesNo(String message) {
+                if (message.startsWith("The authenticity of host")) {
+                    return true;
+                }
+
+                return false;
+            }
+        });
+
+        session.connect();
+    }
+
+    @Test
+    void givenAPuttyKey_whenKeyAuthIsProvided_thenTheConnectionSucceeds() throws Exception {
+        JSch jSch = new JSch();
+        jSch.addIdentity("src/test/resources/com/baeldung/java/io/jsch/nopassphrase/id_rsa.ppk");
+
+        Session session = jSch.getSession(USERNAME, sftpContainer.getHost(), sftpContainer.getMappedPort(SFTP_PORT));
+
+        session.setUserInfo(new BaseUserInfo() {
+            @Override
+            public boolean promptYesNo(String message) {
+                if (message.startsWith("The authenticity of host")) {
+                    return true;
+                }
+
+                return false;
+            }
+        });
+
+        session.connect();
+    }
+
+    @Test
+    void givenAnOpenSSHKeyWithPassphrase_whenKeyAuthIsProvided_thenTheConnectionSucceeds() throws Exception {
+        JSch jSch = new JSch();
+        jSch.addIdentity("src/test/resources/com/baeldung/java/io/jsch/passphrase/id_rsa");
+
+        Session session = jSch.getSession(USERNAME, sftpContainer.getHost(), sftpContainer.getMappedPort(SFTP_PORT));
+
+        session.setUserInfo(new BaseUserInfo() {
+            @Override
+            public String getPassphrase() {
+                return "te5tPa55word";
+            }
+
+            @Override
+            public boolean promptPassphrase(String message) {
+                return true;
+            }
+
+            @Override
+            public boolean promptYesNo(String message) {
+                if (message.startsWith("The authenticity of host")) {
+                    return true;
+                }
+
+                return false;
+            }
+        });
+
+        session.connect();
+    }
+}