It's a time zone change on December 31st in Shanghai.
See this page for details of 1927 in Shanghai. Basically at midnight at the end of 1927, the clocks went back 5 minutes and 52 seconds. So "1927-12-31 23:54:08" actually happened twice, and it looks like Java is parsing it as the later possible instant for that local date/time - hence the difference.
Just another episode in the often weird and wonderful world of time zones.
EDIT: Stop press! History changes...
The original question would no longer demonstrate quite the same behaviour, if rebuilt with version 2013a of TZDB. In 2013a, the result would be 358 seconds, with a transition time of 23:54:03 instead of 23:54:08.
I only noticed this because I'm collecting questions like this in Noda Time, in the form of unit tests... The test has now been changed, but it just goes to show - not even historical data is safe.
EDIT: History has changed again...
In TZDB 2014f, the time of the change has moved to 1900-12-31, and it's now a mere 343 second change (so the time between t
and t+1
is 344 seconds, if you see what I mean).
EDIT: To answer a question around a transition at 1900... it looks like the Java timezone implementation treats all time zones as simply being in their standard time for any instant before the start of 1900 UTC:
import java.util.TimeZone;
public class Test {
public static void main(String[] args) throws Exception {
long startOf1900Utc = -2208988800000L;
for (String id : TimeZone.getAvailableIDs()) {
TimeZone zone = TimeZone.getTimeZone(id);
if (zone.getRawOffset() != zone.getOffset(startOf1900Utc - 1)) {
System.out.println(id);
}
}
}
}
The code above produces no output on my Windows machine. So any time zone which has any offset other than its standard one at the start of 1900 will count that as a transition. TZDB itself has some data going back earlier than that, and doesn't rely on any idea of a "fixed" standard time (which is what getRawOffset
assumes to be a valid concept) so other libraries needn't introduce this artificial transition.
The version number shown describes the version of the JRE the class file is compatible with.
The reported major numbers are:
Java SE 17 = 61,
Java SE 16 = 60,
Java SE 15 = 59,
Java SE 14 = 58,
Java SE 13 = 57,
Java SE 12 = 56,
Java SE 11 = 55,
Java SE 10 = 54,
Java SE 9 = 53,
Java SE 8 = 52,
Java SE 7 = 51,
Java SE 6.0 = 50,
Java SE 5.0 = 49,
JDK 1.4 = 48,
JDK 1.3 = 47,
JDK 1.2 = 46,
JDK 1.1 = 45
(Source: Wikipedia)
To fix the actual problem you should try to either run the Java code with a newer version of Java JRE or specify the target parameter to the Java compiler to instruct the compiler to create code compatible with earlier Java versions.
For example, in order to generate class files compatible with Java 1.4, use the following command line:
javac -target 1.4 HelloWorld.java
With newer versions of the Java compiler you are likely to get a warning about the bootstrap class path not being set. More information about this error is available in a blog post New javac warning for setting an older source without bootclasspath.
Best Answer
Check if tools.jar used during compilation complies with the JRE set. If you are on eclipse, verify the versions as:
Goto Window->Preferences
- Check Ant Runtime by selecting Runtime under Ant in the left pane. Check the Global Entries under classpath tab. You can see the version in folder path.
- On the left pane check installed JREs under Java. Check the version.
I had also got the same problem when my selected JRE was 1.6.0_24 and tools.jar in Ant runtime was coming from jdk 1.7 If both of them are from different versions- 1.6/1.7, correct them by correcting their path. Typically, tools.jar can be found at :C:\Program Files\Java\jdk1.x.x\lib. Likewise if required add the JRE by pointing it to C:\Program Files\Java\jdk1.x.x\