diff --git a/classlib/src/main/java/org/teavm/classlib/java/io/TUncheckedIOException.java b/classlib/src/main/java/org/teavm/classlib/java/io/TUncheckedIOException.java
index 3b32f02b3..bd9e4f2f4 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/io/TUncheckedIOException.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/io/TUncheckedIOException.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.io;
 
 import java.io.IOException;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TByteChannel.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TByteChannel.java
index c8f1231bd..4afe85cb2 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TByteChannel.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TByteChannel.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
 public interface TByteChannel extends TReadableByteChannel, TWritableByteChannel {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TChannel.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TChannel.java
index 484b59bf5..a30e71ed3 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TChannel.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TChannel.java
@@ -1,8 +1,22 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
-import org.teavm.classlib.java.io.TCloseable;
-
 import java.io.IOException;
+import org.teavm.classlib.java.io.TCloseable;
 
 public interface TChannel extends TCloseable {
     boolean isOpen();
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TClosedChannelException.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TClosedChannelException.java
index 891d00a0d..396ba088e 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TClosedChannelException.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TClosedChannelException.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
 import java.io.IOException;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonReadableChannelException.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonReadableChannelException.java
index 46d821740..a4970d16a 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonReadableChannelException.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonReadableChannelException.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
 public class TNonReadableChannelException extends IllegalStateException {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonWritableChannelException.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonWritableChannelException.java
index 62a5117fb..dc0fec646 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonWritableChannelException.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TNonWritableChannelException.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
 public class TNonWritableChannelException extends IllegalStateException {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TReadableByteChannel.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TReadableByteChannel.java
index 5e697f7f4..95c086cc0 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TReadableByteChannel.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TReadableByteChannel.java
@@ -1,8 +1,22 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
-import org.teavm.classlib.java.nio.TByteBuffer;
-
 import java.io.IOException;
+import org.teavm.classlib.java.nio.TByteBuffer;
 
 public interface TReadableByteChannel extends TChannel {
     int read(TByteBuffer dst) throws IOException;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TSeekableByteChannel.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TSeekableByteChannel.java
index dfaa88898..20ef9cfad 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TSeekableByteChannel.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TSeekableByteChannel.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
 import java.io.IOException;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TWritableByteChannel.java b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TWritableByteChannel.java
index 4b601f437..72628894f 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TWritableByteChannel.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/channels/TWritableByteChannel.java
@@ -1,8 +1,22 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.channels;
 
-import org.teavm.classlib.java.nio.TByteBuffer;
-
 import java.io.IOException;
+import org.teavm.classlib.java.nio.TByteBuffer;
 
 public interface TWritableByteChannel extends TChannel {
     int write(TByteBuffer src) throws IOException;
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/file/TAccessDeniedException.java b/classlib/src/main/java/org/teavm/classlib/java/nio/file/TAccessDeniedException.java
index 0d7aef002..e286519c2 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/file/TAccessDeniedException.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/file/TAccessDeniedException.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.file;
 
 public class TAccessDeniedException extends TFileSystemException {
diff --git a/classlib/src/main/java/org/teavm/classlib/java/nio/file/TFileSystemException.java b/classlib/src/main/java/org/teavm/classlib/java/nio/file/TFileSystemException.java
index 61876a652..15b7c788c 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/nio/file/TFileSystemException.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/nio/file/TFileSystemException.java
@@ -1,3 +1,18 @@
+/*
+ *  Copyright 2023 Jonathan Coates.
+ *
+ *  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 org.teavm.classlib.java.nio.file;
 
 import java.io.IOException;
@@ -36,12 +51,20 @@ public class TFileSystemException extends IOException {
 
     @Override
     public String getMessage() {
-        if (file == null && other == null) return reason;
+        if (file == null && other == null) {
+            return reason;
+        }
 
         StringBuilder out = new StringBuilder();
-        if (file != null) out.append(file);
-        if (other != null) out.append(" -> ").append(other);
-        if (reason != null) out.append(": ").append(reason);
+        if (file != null) {
+            out.append(file);
+        }
+        if (other != null) {
+            out.append(" -> ").append(other);
+        }
+        if (reason != null) {
+            out.append(": ").append(reason);
+        }
         return out.toString();
     }
 }