diff --git a/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpServer.java b/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpServer.java
index 5d5ab6d670a7..b97da7064263 100644
--- a/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpServer.java
+++ b/jetty-http-spi/src/main/java/org/eclipse/jetty/http/spi/JettyHttpServer.java
@@ -89,7 +89,7 @@ public void bind(InetSocketAddress addr, int backlog) throws IOException
                 if (connector.getPort() == addr.getPort() || connector.getLocalPort() == addr.getPort())
                 {
                     if (LOG.isDebugEnabled())
-                        LOG.debug("server already bound to port " + addr.getPort() + ", no need to rebind");
+                        LOG.debug("server already bound to port {}, no need to rebind", addr.getPort());
                     return;
                 }
             }
@@ -99,7 +99,7 @@ public void bind(InetSocketAddress addr, int backlog) throws IOException
             throw new IOException("jetty server is not bound to port " + addr.getPort());
 
         if (LOG.isDebugEnabled())
-            LOG.debug("binding server to port " + addr.getPort());
+            LOG.debug("binding server to port {}", addr.getPort());
         ServerConnector connector = new ServerConnector(_server);
         connector.setPort(addr.getPort());
         connector.setHost(addr.getHostName());
diff --git a/jetty-server/src/main/java/org/eclipse/jetty/server/HttpInput.java b/jetty-server/src/main/java/org/eclipse/jetty/server/HttpInput.java
index 855f414eba2f..ea42b67bea2e 100644
--- a/jetty-server/src/main/java/org/eclipse/jetty/server/HttpInput.java
+++ b/jetty-server/src/main/java/org/eclipse/jetty/server/HttpInput.java
@@ -914,7 +914,7 @@ else if (aeof)
                 if (LOG.isDebugEnabled())
                     LOG.warn(msg, e2);
                 else
-                    LOG.warn(msg + ": {}", e2.toString());
+                    LOG.warn("{}: {}", msg, e2.toString());
                 throw new RuntimeIOException(msg, e2);
             }
         }
diff --git a/jetty-server/src/main/java/org/eclipse/jetty/server/handler/ResourceHandler.java b/jetty-server/src/main/java/org/eclipse/jetty/server/handler/ResourceHandler.java
index b3412f56f11b..d4c092603381 100644
--- a/jetty-server/src/main/java/org/eclipse/jetty/server/handler/ResourceHandler.java
+++ b/jetty-server/src/main/java/org/eclipse/jetty/server/handler/ResourceHandler.java
@@ -409,7 +409,7 @@ public void setStylesheet(String stylesheet)
             _stylesheet = Resource.newResource(stylesheet);
             if (!_stylesheet.exists())
             {
-                LOG.warn("unable to find custom stylesheet: " + stylesheet);
+                LOG.warn("unable to find custom stylesheet: {}", stylesheet);
                 _stylesheet = null;
             }
         }
diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/thread/QueuedThreadPool.java b/jetty-util/src/main/java/org/eclipse/jetty/util/thread/QueuedThreadPool.java
index 6022858ab400..9147bf16c46b 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/thread/QueuedThreadPool.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/thread/QueuedThreadPool.java
@@ -267,7 +267,7 @@ protected void doStop() throws Exception
                 }
                 catch (Throwable t)
                 {
-                    LOG.warn("Unable to close job: " + job, t);
+                    LOG.warn("Unable to close job: {}", job, t);
                 }
             }
             else if (job != NOOP)
diff --git a/jetty-websocket/websocket-core-client/src/main/java/org/eclipse/jetty/websocket/core/client/CoreClientUpgradeRequest.java b/jetty-websocket/websocket-core-client/src/main/java/org/eclipse/jetty/websocket/core/client/CoreClientUpgradeRequest.java
index 14f08d7cadfe..b9535643759a 100644
--- a/jetty-websocket/websocket-core-client/src/main/java/org/eclipse/jetty/websocket/core/client/CoreClientUpgradeRequest.java
+++ b/jetty-websocket/websocket-core-client/src/main/java/org/eclipse/jetty/websocket/core/client/CoreClientUpgradeRequest.java
@@ -318,7 +318,7 @@ private void notifyUpgradeListeners(Consumer<UpgradeListener> action)
             }
             catch (Throwable t)
             {
-                LOG.info("Exception while invoking listener " + listener, t);
+                LOG.info("Exception while invoking listener {}", listener, t);
             }
         }
     }
diff --git a/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameCaptureExtension.java b/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameCaptureExtension.java
index 9612f744651d..6a4e7dde8ab0 100644
--- a/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameCaptureExtension.java
+++ b/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameCaptureExtension.java
@@ -128,7 +128,7 @@ private void saveFrame(Frame frame, boolean outgoing)
         }
         catch (IOException e)
         {
-            LOG.warn("Unable to save frame: " + frame, e);
+            LOG.warn("Unable to save frame: {}", frame, e);
         }
         finally
         {
diff --git a/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameFlusher.java b/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameFlusher.java
index c1ea4585efc2..2c46cde71cb3 100644
--- a/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameFlusher.java
+++ b/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/FrameFlusher.java
@@ -460,7 +460,7 @@ protected void notifyCallbackSuccess(Callback callback)
         catch (Throwable x)
         {
             if (LOG.isDebugEnabled())
-                LOG.debug("Exception while notifying success of callback " + callback, x);
+                LOG.debug("Exception while notifying success of callback {}", callback, x);
         }
     }
 
@@ -476,7 +476,7 @@ protected void notifyCallbackFailure(Callback callback, Throwable failure)
         catch (Throwable x)
         {
             if (LOG.isDebugEnabled())
-                LOG.debug("Exception while notifying failure of callback " + callback, x);
+                LOG.debug("Exception while notifying failure of callback {}", callback, x);
         }
     }
 
diff --git a/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/WebSocketCoreSession.java b/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/WebSocketCoreSession.java
index 148d2fcf0ede..c67abcc63d65 100644
--- a/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/WebSocketCoreSession.java
+++ b/jetty-websocket/websocket-core-common/src/main/java/org/eclipse/jetty/websocket/core/internal/WebSocketCoreSession.java
@@ -529,7 +529,7 @@ public void sendFrame(Frame frame, Callback callback, boolean batch)
         catch (Throwable t)
         {
             if (LOG.isDebugEnabled())
-                LOG.warn("Invalid outgoing frame: " + frame, t);
+                LOG.warn("Invalid outgoing frame: {}", frame, t);
 
             callback.failed(t);
             return;
diff --git a/jetty-websocket/websocket-jetty-server/src/test/java/org/eclipse/jetty/websocket/server/browser/BrowserSocket.java b/jetty-websocket/websocket-jetty-server/src/test/java/org/eclipse/jetty/websocket/server/browser/BrowserSocket.java
index 14264e68a228..08a6be2a8581 100644
--- a/jetty-websocket/websocket-jetty-server/src/test/java/org/eclipse/jetty/websocket/server/browser/BrowserSocket.java
+++ b/jetty-websocket/websocket-jetty-server/src/test/java/org/eclipse/jetty/websocket/server/browser/BrowserSocket.java
@@ -153,7 +153,7 @@ public void onTextMessage(String message)
             catch (IOException e)
             {
                 writeMessage("Unable to read resource: " + name);
-                LOG.warn("Unable to read resource: " + name, e);
+                LOG.warn("Unable to read resource: {}", name, e);
             }
             return;
         }