(original) (raw)

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 kinds,

boolean recurse)

throws IOException

{

checkNotModuleOrientedLocation(location);

// validatePackageName(packageName);

nullCheck(packageName);

nullCheck(kinds);

Iterable 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 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 "CLASS\_NAME";

}

}, "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