Make sure the vanilla java builder closes its JavaFileManager.

I observed that before this change, large vanilla Java builds could exhaust the file descriptor limit of java builder worker processes.

Closes bazelbuild#6695.

PiperOrigin-RevId: 222693636

src/java_tools/buildjar/java/com/google/devtools/build/buildjar/VanillaJavaBuilder.java

@@ -152,29 +152,28 @@ public VanillaJavaBuilderResult run(List<String> args) throws IOException {
  DiagnosticCollector<JavaFileObject> diagnosticCollector = new DiagnosticCollector<>();
  StringWriter output = new StringWriter();
  JavaCompiler javaCompiler = ToolProvider.getSystemJavaCompiler();
- StandardJavaFileManager fileManager =
- javaCompiler.getStandardFileManager(diagnosticCollector, ENGLISH, UTF_8);
-
  Path tempDir = Paths.get(firstNonNull(optionsParser.getTempDir(), "_tmp"));
  Path nativeHeaderDir = tempDir.resolve("native_headers");
  Files.createDirectories(nativeHeaderDir);
-
- setLocations(optionsParser, fileManager, nativeHeaderDir);
- ImmutableList<JavaFileObject> sources = getSources(optionsParser, fileManager);
  boolean ok;
- if (sources.isEmpty()) {
- ok = true;
- } else {
- CompilationTask task =
- javaCompiler.getTask(
- new PrintWriter(output, true),
- fileManager,
- diagnosticCollector,
- JavacOptions.removeBazelSpecificFlags(optionsParser.getJavacOpts()),
- ImmutableList.<String>of() /*classes*/,
- sources);
- setProcessors(optionsParser, fileManager, task);
- ok = task.call();
+ try (StandardJavaFileManager fileManager =
+ javaCompiler.getStandardFileManager(diagnosticCollector, ENGLISH, UTF_8)) {
+ setLocations(optionsParser, fileManager, nativeHeaderDir);
+ ImmutableList<JavaFileObject> sources = getSources(optionsParser, fileManager);
+ if (sources.isEmpty()) {
+ ok = true;
+ } else {
+ CompilationTask task =
+ javaCompiler.getTask(
+ new PrintWriter(output, true),
+ fileManager,
+ diagnosticCollector,
+ JavacOptions.removeBazelSpecificFlags(optionsParser.getJavacOpts()),
+ ImmutableList.<String>of() /*classes*/,
+ sources);
+ setProcessors(optionsParser, fileManager, task);
+ ok = task.call();
+ }
  }
  if (ok) {
  writeOutput(optionsParser);