Possible open file leak in com.sun.tools.javac.file.JavacFileManager (original) (raw)

Andreas Fey fey at apiomat.com
Mon Nov 12 07:13:57 UTC 2018

Jon,

is there an<y progress here? I would be a pleasure to me to be your beta tester ;-)

Thanks,

Andreas

On 11/5/18 15:55 AM, Jonathan Gibbons wrote:

Andreas,

We'll take a look. -- Jon

On 11/5/18 6:24 AM, Andreas Fey wrote: Hi all, we maybe found a bug in the com.sun.tools.javac.file.JavacFileManager; our tool makes heavy use of compiling classes during runtime, and after switching from JDK 8 to 11, we noticed hundreds of open files being created during list() and only closed when JVM exists. The concerning lines of code are: @Override @DefinedBy(Api.COMPILER) public Iterable list(Location location, String packageName, Set<JavaFileObject.Kind> kinds, boolean recurse) throws IOException { checkNotModuleOrientedLocation(location); // validatePackageName(packageName); nullCheck(packageName); nullCheck(kinds); Iterable<? extends Path> path = getLocationAsPaths(location); if (path == null) return List.nil(); RelativeDirectory subdirectory = RelativeDirectory.forPackage(packageName); ListBuffer results = new ListBuffer<>(); for (Path directory : path) { Container container = getContainer(directory); container.list(directory, subdirectory, kinds, recurse, results); } return results.toList(); } We think, a container.close() is missing in the for loop. Without this, a filehandle is created for every container/directiry found here. To test this, the following code snipped can be used, but the location must be set property to find a valid path != null: @Test public void testFileManager( ) throws IOException { countOpenFiles( ); final Set<javax.tools.JavaFileObject.Kind> kinds = new HashSet<>( ); kinds.add( javax.tools.JavaFileObject.Kind.OTHER ); kinds.add( javax.tools.JavaFileObject.Kind.SOURCE ); kinds.add( javax.tools.JavaFileObject.Kind.CLASS ); kinds.add( javax.tools.JavaFileObject.Kind.HTML ); final StandardJavaFileManager sfm = ToolProvider.getSystemJavaCompiler( ).getStandardFileManager( null, null, null ); sfm.list( new JavaFileManager.Location( ) { @Override public boolean isOutputLocation( ) { return false; } @Override public String getName( ) { return "CLASSNAME"; } }, "com", kinds, true ); countOpenFiles( ); } private void countOpenFiles( ) { final String processName = java.lang.management.ManagementFactory.getRuntimeMXBean( ).getName( ); final long pid = Long.parseLong( processName.split( "@" )[ 0 ] ); try { final Runtime rt = Runtime.getRuntime( ); final Process pr = rt.exec( "lsof -p " + pid ); int ctr = 0; final BufferedReader br = new BufferedReader( new InputStreamReader( pr.getInputStream( ) ) ); while ( ( br.readLine( ) ) != null ) ctr++; pr.waitFor( ); pr.destroy( ); System.out.println( "Open files: " + ctr ); } catch ( final Exception e ) { e.printStackTrace( ); } } Can anybody confirm this? Best, Andreas

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