CodeServer doesn't close log files after writing, tries to delete parent directory

[niloc132]

I tried to use 2.13 with my project. Compiling and running by using the eclipse plugin.
I got the 404 Errors, and tried the suggested method to add -server com.google.gwt.dev.shell.JettyLauncher.
This did not work, because of

Unable to load server class com.google.gwt.dev.shell.JettyLauncher by fully qualified name or from the service loader
java.lang.ClassNotFoundException: com.google.gwt.dev.shell.JettyLauncher

Seems like the package name is wrong. Should be com.google.gwt.dev.shell.jetty.JettyLauncher.

After fixing that, i get this error:

Compile with -strict or with -logLevel set to TRACE or DEBUG to see all errors.
   Module setup completed in 6203 ms
java.nio.file.FileSystemException: D:\temp\system\gwt-codeserver-6436482415766710969\me.jhost.webapp\compile-1: failed to delete one or more files; see suppressed exceptions for details
	at com.google.gwt.thirdparty.guava.common.io.MoreFiles.throwDeleteFailed(MoreFiles.java:803)
	at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursively(MoreFiles.java:554)
	at com.google.gwt.dev.codeserver.OutboxDir.create(OutboxDir.java:91)
	at com.google.gwt.dev.codeserver.CodeServer.makeOutboxTable(CodeServer.java:182)
	at com.google.gwt.dev.codeserver.CodeServer.start(CodeServer.java:151)
	at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:104)
	at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:55)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:569)
	at com.google.gwt.dev.shell.SuperDevListener.runCodeServer(SuperDevListener.java:118)
	at com.google.gwt.dev.shell.SuperDevListener.start(SuperDevListener.java:97)
	at com.google.gwt.dev.DevMode.ensureCodeServerListener(DevMode.java:705)
	at com.google.gwt.dev.DevModeBase.doStartup(DevModeBase.java:778)
	at com.google.gwt.dev.DevMode.doStartup(DevMode.java:599)
	at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:880)
	at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:698)
	at com.google.gwt.dev.DevMode.main(DevMode.java:476)
	Suppressed: java.nio.file.FileSystemException: D:\temp\system\gwt-codeserver-6436482415766710969\me.jhost.webapp\compile-1\compile.log: Der Prozess kann nicht auf die Datei zugreifen, da sie von einem anderen Prozess verwendet wird
		at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:92)
		at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
		at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
		at java.base/sun.nio.fs.WindowsFileSystemProvider.implDelete(WindowsFileSystemProvider.java:275)
		at java.base/sun.nio.fs.AbstractFileSystemProvider.delete(AbstractFileSystemProvider.java:105)
		at java.base/java.nio.file.Files.delete(Files.java:1152)
		at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursivelyInsecure(MoreFiles.java:678)
		at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteDirectoryContentsInsecure(MoreFiles.java:698)
		at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursivelyInsecure(MoreFiles.java:671)
		at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursively(MoreFiles.java:543)
		... 17 more

The german message (Der Prozess kann nicht auf die Datei zugreifen, da sie von einem anderen Prozess verwendet wird) translates to something like 'The Process can not access the file, because it is used by another process'.
I've checked that, but the folder has just been created by launching the app. Never had an issue like that with older GWT Releases.

Originally posted by @keinhaar in #10271

Root cause appears to be that PrintWriterTreeLogger instance do not close the PrintWriter they create, and then the same process tries to delete the file that's still technically held open. This isnt a regression per se - it has always been wrong - but it is a new problem now that we're stricter about actually cleaning up after ourselves.

Alternative fix is we could clean the "outbox" dir before we create the dummy compile entry, so that the compiler hasn't had a chance to write to it yet. That would better solve the immediate problem, and would sidestep any other leaked FDs during startup.

[niloc132]

It appears that this is something of a "known issue" it seems, that windows can prevent this:

gwt/dev/codeserver/java/com/google/gwt/dev/codeserver/OutboxDir.java

Lines 87 to 96 in b7117c1

	// Try to clean up existing subdirectories.
	// (This is not guaranteed to delete all directories on Windows if a directory is locked.)
	for (File candidate : children) {
	if (candidate.getName().startsWith(COMPILE_DIR_PREFIX)) {
	MoreFiles.deleteRecursively(candidate.toPath(), RecursiveDeleteOption.ALLOW_INSECURE);
	if (candidate.exists()) {
	logger.log(Type.WARN, "unable to delete '" + candidate + "' (skipped)");
	}
	}
	}

Another Windows tester for the release confirms that this isn't happening for them, so there might be something environmental playing a role (which doesn't minimize the fact that it needs to be fixed) - @keinhaar can you confirm your windows and java versions?

[keinhaar]

Tested on Windows 11 23H2 with java 17

[FrankHossfeld]

@keinhaar I can not reproduce the issue. Set up a Windows VM added Java 17 and maven, created a new project using the TBroyer gwt-maven-archetype. Everything works fine.

can you share some more information about your project please.

Does it have the client-, shared- and server-code separated?

Is the project based on Maven? If so, does it work in case you run it from the command line?

[keinhaar]

My Project is not maven based. Its completely in Eclipse using the GWT Plugin.
Client, Shared and Server Code are separated in individual projects.
I get the Error when starting the dev-mode from eclipse.

[craigmit]

I got this issue when I accidently ran the client twice.

1. In samples\dynatable.
2. Open a command and run mvn gwt:codeserver -pl dynatable-client -am
3. Open another command and run it again mvn gwt:codeserver -pl dynatable-client -am

Output:

[INFO] --- gwt:1.2.0:codeserver (default-cli) @ dynatable ---
[INFO] Ignoring com.google.gwt.sample.dynatable:dynatable-shared:jar:1.0-SNAPSHOT; neither a gwt-lib or jar:sources; Did you forget to use <type>gwt-lib</type> in the dependency declaration?
[INFO] Turning off precompile in incremental mode.
[INFO] Super Dev Mode starting up
[INFO]    workDir: C:\Projects\code\TestProject\gwt-2.13.0\samples\dynatable\target\gwt\codeserver
[WARNING] java.nio.file.FileSystemException: C:\Projects\code\TestProject\gwt-2.13.0\samples\dynatable\target\gwt\codeserver\com.google.gwt.sample.dynatable.App\compile-1: failed to delete one or more files; see suppressed exceptions for details
[WARNING]       at com.google.gwt.thirdparty.guava.common.io.MoreFiles.throwDeleteFailed(MoreFiles.java:803)
[WARNING]       at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursively(MoreFiles.java:554)
[WARNING]       at com.google.gwt.dev.codeserver.OutboxDir.create(OutboxDir.java:91)
[WARNING]       at com.google.gwt.dev.codeserver.CodeServer.makeOutboxTable(CodeServer.java:182)
[WARNING]       at com.google.gwt.dev.codeserver.CodeServer.start(CodeServer.java:151)
[WARNING]       at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:104)
[WARNING]       at com.google.gwt.dev.codeserver.CodeServer.main(CodeServer.java:55)
[WARNING]       Suppressed: java.nio.file.FileSystemException: C:\Projects\code\TestProject\gwt-2.13.0\samples\dynatable\target\gwt\codeserver\com.google.gwt.sample.dynatable.App\compile-1\compile.log: The process cannot access the file because it is being used by another process
[WARNING]               at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:92)
[WARNING]               at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
[WARNING]               at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
[WARNING]               at java.base/sun.nio.fs.WindowsFileSystemProvider.implDelete(WindowsFileSystemProvider.java:273)
[WARNING]               at java.base/sun.nio.fs.AbstractFileSystemProvider.delete(AbstractFileSystemProvider.java:104)
[WARNING]               at java.base/java.nio.file.Files.delete(Files.java:1152)
[WARNING]               at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursivelyInsecure(MoreFiles.java:678)
[WARNING]               at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteDirectoryContentsInsecure(MoreFiles.java:698)
[WARNING]               at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursivelyInsecure(MoreFiles.java:671)
[WARNING]               at com.google.gwt.thirdparty.guava.common.io.MoreFiles.deleteRecursively(MoreFiles.java:543)
[WARNING]               ... 5 more
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for dynatable 1.0-SNAPSHOT:
[INFO]
[INFO] dynatable .......................................... FAILURE [  2.328 s]
[INFO] dynatable-shared ................................... SKIPPED
[INFO] dynatable-client ................................... SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.992 s
[INFO] Finished at: 2026-02-10T14:14:54+11:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal net.ltgt.gwt.maven:gwt-maven-plugin:1.2.0:codeserver (default-cli) on project dynatable: Process exited with an error: 1 (Exit value: 1) -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

However, when I stop the other codeserver, everything is fine.

[niloc132]

Good to know - not unexpected (on Windows at least), and should also be "solved" with the proposed patch (though it would still fail as the codeserver port is already bound by the other process, as it should).