Use try-with-resources (#999)

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

src/main/java/com/hierynomus/sshj/userauth/keyprovider/OpenSSHKeyFileUtil.java

@@ -47,8 +47,7 @@ public class OpenSSHKeyFileUtil {
      * @param publicKey Public key accessible through a {@code Reader}
      */
     public static ParsedPubKey initPubKey(Reader publicKey) throws IOException {
-        final BufferedReader br = new BufferedReader(publicKey);
+        try (BufferedReader br = new BufferedReader(publicKey)) {
-        try {
             String keydata;
             while ((keydata = br.readLine()) != null) {
                 keydata = keydata.trim();
@@ -68,8 +67,6 @@ public class OpenSSHKeyFileUtil {
             throw new IOException("Public key file is blank");
         } catch (Base64DecodingException err) {
             throw new IOException("Public key decoding failed", err);
-        } finally {
-            br.close();
         }
     }
 

src/main/java/net/schmizz/sshj/sftp/RandomAccessRemoteFile.java

@@ -317,13 +317,10 @@ public class RandomAccessRemoteFile
     @Override
     public void writeUTF(String str)
             throws IOException {
-        final DataOutputStream dos = new DataOutputStream(rf.new RemoteFileOutputStream(fp));
+        try (DataOutputStream dos = new DataOutputStream(rf.new RemoteFileOutputStream(fp));) {
-        try {
             dos.writeUTF(str);
-        } finally {
-            dos.close();
-        }
             fp += dos.size();
         }
+    }
 
 }

src/main/java/net/schmizz/sshj/sftp/SFTPFileTransfer.java

@@ -140,12 +140,9 @@ public class SFTPFileTransfer
                                           final LocalDestFile local)
                 throws IOException {
             final LocalDestFile adjusted = local.getTargetDirectory(remote.getName());
-            final RemoteDirectory rd = engine.openDir(remote.getPath());
+            try (RemoteDirectory rd = engine.openDir(remote.getPath())) {
-            try {
                 for (RemoteResourceInfo rri : rd.scan(getDownloadFilter()))
                     download(listener, rri, adjusted.getChild(rri.getName()), 0); // not supporting individual byte offsets for these files
-            } finally {
-                rd.close();
             }
             return adjusted;
         }
@@ -156,23 +153,16 @@ public class SFTPFileTransfer
                                            final long byteOffset)
                 throws IOException {
             final LocalDestFile adjusted = local.getTargetFile(remote.getName());
-            final RemoteFile rf = engine.open(remote.getPath());
+            try (RemoteFile rf = engine.open(remote.getPath())) {
-            try {
                 log.debug("Attempting to download {} with offset={}", remote.getPath(), byteOffset);
-                final RemoteFile.ReadAheadRemoteFileInputStream rfis = rf.new ReadAheadRemoteFileInputStream(16, byteOffset);
+                try (RemoteFile.ReadAheadRemoteFileInputStream rfis = rf.new ReadAheadRemoteFileInputStream(16, byteOffset);
-                final OutputStream os = adjusted.getOutputStream(byteOffset != 0);
+                     OutputStream os = adjusted.getOutputStream(byteOffset != 0)) {
-                try {
                     new StreamCopier(rfis, os, engine.getLoggerFactory())
                             .bufSize(engine.getSubsystem().getLocalMaxPacketSize())
                             .keepFlushing(false)
                             .listener(listener)
                             .copy();
-                } finally {
-                    rfis.close();
-                    os.close();
                 }
-            } finally {
-                rf.close();
             }
             return adjusted;
         }

src/main/java/net/schmizz/sshj/transport/verification/OpenSSHKnownHosts.java

@@ -187,12 +187,9 @@ public class OpenSSHKnownHosts
 
     public void write()
             throws IOException {
-        final BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(khFile));
+        try (BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(khFile))) {
-        try {
             for (KnownHostEntry entry : entries)
                 bos.write((entry.getLine() + LS).getBytes(StandardCharsets.UTF_8));
-        } finally {
-            bos.close();
         }
     }
 

src/main/java/net/schmizz/sshj/userauth/keyprovider/PuTTYKeyFile.java

@@ -200,9 +200,8 @@ public class PuTTYKeyFile extends BaseFileKeyProvider {
 
     protected void parseKeyPair() throws IOException {
         this.keyFileVersion = null;
-        BufferedReader r = new BufferedReader(resource.getReader());
         // Parse the text into headers and payloads
-        try {
+        try (BufferedReader r = new BufferedReader(resource.getReader())) {
             String headerName = null;
             String line;
             while ((line = r.readLine()) != null) {
@@ -225,8 +224,6 @@ public class PuTTYKeyFile extends BaseFileKeyProvider {
                     payload.put(headerName, s);
                 }
             }
-        } finally {
-            r.close();
         }
         if (this.keyFileVersion == null) {
             throw new IOException("Invalid key file format: missing \"PuTTY-User-Key-File-?\" entry");