diff --git a/src/main/java/net/schmizz/sshj/common/StreamCopier.java b/src/main/java/net/schmizz/sshj/common/StreamCopier.java
index 66fbee76..622ee4d2 100644
--- a/src/main/java/net/schmizz/sshj/common/StreamCopier.java
+++ b/src/main/java/net/schmizz/sshj/common/StreamCopier.java
@@ -107,7 +107,7 @@ public class StreamCopier {
                     log.debug("Done copying from {}", in);
                     doneEvent.set();
                 } catch (IOException ioe) {
-                    log.error("In pipe from {} to {}: " + ioe.toString(), in, out);
+                    log.error("In pipe from {} to {}: {}", new Object[] { in, out, ioe });
                     doneEvent.deliverError(ioe);
                 }
             }
@@ -136,7 +136,7 @@ public class StreamCopier {
 
         final double timeSeconds = (System.currentTimeMillis() - startTime) / 1000.0;
         final double sizeKiB = count / 1024.0;
-        log.info(sizeKiB + " KiB transferred  in {} seconds ({} KiB/s)", timeSeconds, (sizeKiB / timeSeconds));
+        log.info("{} KiB transferred  in {} seconds ({} KiB/s)", new Object[] { sizeKiB, timeSeconds, (sizeKiB / timeSeconds) });
 
         if (length != -1 && read == -1)
             throw new IOException("Encountered EOF, could not transfer " + length + " bytes");
@@ -154,4 +154,4 @@ public class StreamCopier {
         return count;
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/main/java/net/schmizz/sshj/connection/channel/Window.java b/src/main/java/net/schmizz/sshj/connection/channel/Window.java
index 44f6bfae..7016e4d6 100644
--- a/src/main/java/net/schmizz/sshj/connection/channel/Window.java
+++ b/src/main/java/net/schmizz/sshj/connection/channel/Window.java
@@ -57,7 +57,7 @@ public abstract class Window {
             throws ConnectionException {
         synchronized (lock) {
             size -= dec;
-            log.debug("Consuming by " + dec + " down to " + size);
+            log.debug("Consuming by {} down to {}", dec, size);
             if (size < 0)
                 throw new ConnectionException("Window consumed to below 0");
         }
diff --git a/src/main/java/net/schmizz/sshj/connection/channel/forwarded/SocketForwardingConnectListener.java b/src/main/java/net/schmizz/sshj/connection/channel/forwarded/SocketForwardingConnectListener.java
index 415ecbe4..c3c0abe0 100644
--- a/src/main/java/net/schmizz/sshj/connection/channel/forwarded/SocketForwardingConnectListener.java
+++ b/src/main/java/net/schmizz/sshj/connection/channel/forwarded/SocketForwardingConnectListener.java
@@ -44,7 +44,7 @@ public class SocketForwardingConnectListener
     @Override
     public void gotConnect(Channel.Forwarded chan)
             throws IOException {
-        log.info("New connection from " + chan.getOriginatorIP() + ":" + chan.getOriginatorPort());
+        log.info("New connection from {}:{}", chan.getOriginatorIP(), chan.getOriginatorPort());
 
         final Socket sock = new Socket();
         sock.setSendBufferSize(chan.getLocalMaxPacketSize());
@@ -66,4 +66,4 @@ public class SocketForwardingConnectListener
         SocketStreamCopyMonitor.monitor(5, TimeUnit.SECONDS, chan2soc, soc2chan, chan, sock);
     }
 
-}
\ No newline at end of file
+}
diff --git a/src/main/java/net/schmizz/sshj/sftp/StatefulSFTPClient.java b/src/main/java/net/schmizz/sshj/sftp/StatefulSFTPClient.java
index 48209b1c..6947474c 100644
--- a/src/main/java/net/schmizz/sshj/sftp/StatefulSFTPClient.java
+++ b/src/main/java/net/schmizz/sshj/sftp/StatefulSFTPClient.java
@@ -31,7 +31,7 @@ public class StatefulSFTPClient
             throws IOException {
         super(engine);
         this.cwd = getSFTPEngine().canonicalize(".");
-        log.info("Start dir = " + cwd);
+        log.info("Start dir = {}", cwd);
     }
 
     private synchronized String cwdify(String path) {
@@ -44,7 +44,7 @@ public class StatefulSFTPClient
         if (statExistence(cwd) == null) {
             throw new SFTPException(cwd + ": does not exist");
         }
-        log.info("CWD = " + cwd);
+        log.info("CWD = {}", cwd);
     }
 
     public synchronized List<RemoteResourceInfo> ls()