Timestamps are not preserved when copying app into container

[jkutner]

When local files (from --path) are copied into the container, they get a last-modified timestamp of 1970-01-01 00:00:00 instead of preserving the timestamp from local.

This causes a problem with spring-boot, which tries to validate the files in an executable JAR file before starting:

Exception in thread "main" java.time.DateTimeException: Invalid value for MonthOfYear (valid values 1 - 12): 0
        at java.time.temporal.ValueRange.checkValidValue(ValueRange.java:311)
        at java.time.temporal.ChronoField.checkValidValue(ChronoField.java:703)
        at java.time.LocalDate.of(LocalDate.java:267)
        at java.time.LocalDateTime.of(LocalDateTime.java:336)
        at org.springframework.boot.loader.jar.CentralDirectoryFileHeader.decodeMsDosFormatDateTime(CentralDirectoryFileHeader.java:130)
        at org.springframework.boot.loader.jar.CentralDirectoryFileHeader.getTime(CentralDirectoryFileHeader.java:119)
        at org.springframework.boot.loader.jar.JarEntry.<init>(JarEntry.java:55)
        at org.springframework.boot.loader.jar.JarFileEntries.getEntry(JarFileEntries.java:328)
        at org.springframework.boot.loader.jar.JarFileEntries.access$400(JarFileEntries.java:48)
        at org.springframework.boot.loader.jar.JarFileEntries$EntryIterator.next(JarFileEntries.java:379)
        at org.springframework.boot.loader.jar.JarFileEntries$EntryIterator.next(JarFileEntries.java:363)
        at org.springframework.boot.loader.jar.JarFile$2.nextElement(JarFile.java:198)
        at org.springframework.boot.loader.jar.JarFile$2.nextElement(JarFile.java:189)
        at org.springframework.boot.loader.archive.JarFileArchive$EntryIterator.next(JarFileArchive.java:186)
        at org.springframework.boot.loader.archive.JarFileArchive$EntryIterator.next(JarFileArchive.java:171)
        at org.springframework.boot.loader.archive.JarFileArchive.getNestedArchives(JarFileArchive.java:84)
        at org.springframework.boot.loader.ExecutableArchiveLauncher.getClassPathArchives(ExecutableArchiveLauncher.java:70)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:49)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

The first file that triggers this is usually META-INF/maven/com.example/java-getting-started/pom.xml, which is the first file the Spring ExecutableArchiveLauncher hits with a timestamp of 1970-01-01 00:00:00

[djoyahoy]

@jkutner We ended up writing all file times at January 1, 1980 00:00:1. This is because zip files (jars) use MS-DOS format for their file times and the epoch for those is Jan 1, 1980. This prevents a cascading failure with the JDK as noted here: https://bugs.openjdk.java.net/browse/JDK-8184940

Additionally, we wanted to stick to a known date and time for all files with an aim towards reproducible builds.