Switch to use Instant

Author: sluongng

src/main/java/com/google/devtools/build/lib/profiler/JsonTraceFileWriter.java

@@ -24,6 +24,7 @@
 import java.io.OutputStreamWriter;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
+import java.time.Instant;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.UUID;
@@ -172,16 +173,15 @@ public void run() {
               // The buffer size of 262144 is chosen at random.
               new OutputStreamWriter(
                   new BufferedOutputStream(outStream, 262144), StandardCharsets.UTF_8))) {
-        var finishDate = new Date();
+        var finishDate = Instant.now();
         writer.beginObject();
         writer.name("otherData");
         writer.beginObject();
         writer.name("bazel_version").value(BlazeVersionInfo.instance().getReleaseName());
         writer.name("build_id").value(buildID.toString());
         writer.name("output_base").value(outputBase);
-        // deprecated, use profile_finish_ts instead
         writer.name("date").value(finishDate.toString());
-        writer.name("profile_finish_ts").value(finishDate.getTime() * 1_000);
+        writer.name("profile_finish_ts").value(finishDate.getEpochSecond() * 1000);
         writer.endObject();
         writer.name("traceEvents");
         writer.beginArray();