Fix jarinfer cli output determinism (#884)

When invoking CLI, jar output sha is not constant. This breaks
cacheability in build systems like Buck and Bazel.
Binary investigation (see attached screenshot) of these jars show byte
0xa-0xd in PkZip header is what is changes, and corresponds to file
modified date/time (see
https://users.cs.jmu.edu/buchhofp/forensics/formats/pkzip.html).
This PR is setting these times to 0 explicilty, so that jar sha remains
constant between invocation.


---------

Co-authored-by: Manu Sridharan <msridhar@gmail.com>

jar-infer/jar-infer-lib/src/main/java/com/uber/nullaway/jarinfer/BytecodeAnnotator.java

@@ -212,6 +212,18 @@ public static void annotateBytecodeInClass(
  annotateBytecode(is, os, nonnullParams, nullableReturns, javaxNullableDesc, javaxNonnullDesc);
  }
 
+ /**
+ * Create a zip entry with creation time of 0 to ensure that jars always have the same checksum.
+ *
+ * @param name of the zip entry.
+ * @return the zip entry.
+ */
+ private static ZipEntry createZipEntry(String name) {
+ ZipEntry entry = new ZipEntry(name);
+ entry.setTime(0);
+ return entry;
+ }
+
  private static void copyAndAnnotateJarEntry(
  JarEntry jarEntry,
  InputStream is,
@@ -224,7 +236,7 @@ private static void copyAndAnnotateJarEntry(
  throws IOException {
  String entryName = jarEntry.getName();
  if (entryName.endsWith(".class")) {
- jarOS.putNextEntry(new ZipEntry(jarEntry.getName()));
+ jarOS.putNextEntry(createZipEntry(jarEntry.getName()));
  annotateBytecode(is, jarOS, nonnullParams, nullableReturns, nullableDesc, nonnullDesc);
  } else if (entryName.equals("META-INF/MANIFEST.MF")) {
  // Read full file
@@ -241,7 +253,7 @@ private static void copyAndAnnotateJarEntry(
  if (!manifestText.equals(manifestMinusDigests) && !stripJarSignatures) {
  throw new SignedJarException(SIGNED_JAR_ERROR_MESSAGE);
  }
- jarOS.putNextEntry(new ZipEntry(jarEntry.getName()));
+ jarOS.putNextEntry(createZipEntry(jarEntry.getName()));
  jarOS.write(manifestMinusDigests.getBytes(UTF_8));
  } else if (entryName.startsWith("META-INF/")
  && (entryName.endsWith(".DSA")
@@ -251,7 +263,7 @@ private static void copyAndAnnotateJarEntry(
  throw new SignedJarException(SIGNED_JAR_ERROR_MESSAGE);
  } // the case where stripJarSignatures==true is handled by default by skipping these files
  } else {
- jarOS.putNextEntry(new ZipEntry(jarEntry.getName()));
+ jarOS.putNextEntry(createZipEntry(jarEntry.getName()));
  jarOS.write(IOUtils.toByteArray(is));
  }
  jarOS.closeEntry();
@@ -329,7 +341,7 @@ public static void annotateBytecodeInAar(
  while (zipIterator.hasNext()) {
  ZipEntry zipEntry = zipIterator.next();
  InputStream is = inputZip.getInputStream(zipEntry);
- zipOS.putNextEntry(new ZipEntry(zipEntry.getName()));
+ zipOS.putNextEntry(createZipEntry(zipEntry.getName()));
  if (zipEntry.getName().equals("classes.jar")) {
  JarInputStream jarIS = new JarInputStream(is);
  JarEntry inputJarEntry = jarIS.getNextJarEntry();