Win a copy of Svelte and Sapper in Action this week in the JavaScript forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Ron McLeod
  • Paul Clapham
  • Bear Bibeault
  • Junilu Lacar
Sheriffs:
  • Jeanne Boyarsky
  • Tim Cooke
  • Henry Wong
Saloon Keepers:
  • Tim Moores
  • Stephan van Hulst
  • Tim Holloway
  • salvin francis
  • Frits Walraven
Bartenders:
  • Scott Selikoff
  • Piet Souris
  • Carey Brown

Java Date

 
Ranch Hand
Posts: 173
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Folks

I have these lines of code



The problem is when I make a call to another method like this:


I am getting a java.lang.NumberFormatException: null

I am not sure why I am getting this, hope someone can advise. Thanks.
 
Rancher
Posts: 43016
76
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Please post an SSCCE (<-- that's a link) that demonstrates the issue. I think we need more context to investigate.
 
Marshal
Posts: 70258
282
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Stop using Date. Use the Java8 classes instead.
 
Ranch Hand
Posts: 198
Oracle Spring Java
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
The code you posted works perfectly.. seems the problem is somewhere else in your code. Check if you are assigning the value properly.
 
Ulf Dittmer
Rancher
Posts: 43016
76
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Stop using Date. Use the Java8 classes instead.


... assuming using Java 8 is feasible. In many environments it's not (yet) an option.
 
Prabhakar Reddy Bokka
Ranch Hand
Posts: 198
Oracle Spring Java
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Campbell Ritchie wrote:Stop using Date. Use the Java8 classes instead.



Not sure how many applications are upgraded to java8. Many applications are still using java 5/6. Practically this may not be possible if your application using lower version of java.
 
Bartender
Posts: 11445
19
Android Google Web Toolkit Mac Eclipse IDE Ubuntu Java
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Ulf Dittmer wrote:

Stop using Date. Use the Java8 classes instead.


... assuming using Java 8 is feasible. In many environments it's not (yet) an option.


Indeed! Sometimes it is frustrating to see how slowly environments upgrade their min version
 
Ulf Dittmer
Rancher
Posts: 43016
76
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Practically this may not be possible if your application using lower version of java.


That brings us back to my first post, then. Post a complete, compilable example that demonstrates the problem.
 
Campbell Ritchie
Marshal
Posts: 70258
282
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Ulf Dittmer wrote: . . .
... assuming using Java 8 is feasible. In many environments it's not (yet) an option.

In which case you would use Joda Time. That looks very similar to the Java8 classes. I think Java8 probably simply imported Joda Time.
 
Ulf Dittmer
Rancher
Posts: 43016
76
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

In which case you would use Joda Time


I don't think that it is good advice for someone who has a problem with API X to use API Y instead. The first step is to figure *why* there is a problem with API X. Only then -and after knowing a good deal more about the situation than we know now- can a recommendation to use API Y make sense. Any possibly not even then.
 
Java Cowboy
Posts: 16084
88
Android Scala IntelliJ IDE Spring Java
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Your mistake is in the format string: "dd-MM-yyyy hh:mm:ss"

Note that "hh" stands for hours, but in 12-hour clock format (hours 1 - 12).

Looking at the date string you are trying to parse, you actually want "HH" instead of "hh" - "HH" is 24-hour clock (hours 0 - 23).

So. change the format string to this: "dd-MM-yyyy HH:mm:ss"
 
Bartender
Posts: 10777
71
Hibernate Eclipse IDE Ubuntu
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Ulf Dittmer wrote:I don't think that it is good advice for someone who has a problem with API X to use API Y instead. The first step is to figure *why* there is a problem with API X. Only then -and after knowing a good deal more about the situation than we know now- can a recommendation to use API Y make sense. Any possibly not even then.


In general, I'd agree with you; but Java's date/time API is so bad (particularly Calendar) that it has pretty much always needed an alternative - and before version 8, that was Joda time. And I say that as someone who loves the language.

Example: I've been using Java for 13 years, and I still don't know all the ramifications of clear()ing a Calendar field - at least not ALL of the 16 that you can clear(); not to mention the 22 or more (out of a total of 54) that it might affect.

Calendar is just a horrible interface, and I echo Maneesh's words about why it's taken so darn long to replace it.

Winston
 
Campbell Ritchie
Marshal
Posts: 70258
282
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I think you are both right, Ulf and Winston. Sorry for confusing things.
 
Ulf Dittmer
Rancher
Posts: 43016
76
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Winston Gutkowski wrote:Calendar is just a horrible interface


I agree, which is why I use java.util.Date to this day if no time zone and DST support is required, and why I initially created https://coderanch.com/how-to/java/JavaDatesFaq to teach people how to make do without using Calendar if possible.
 
It is no measure of health to be well adjusted to a profoundly sick society. -Krishnamurti Tiny ad:
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop
https://coderanch.com/wiki/718759/books/Building-World-Backyard-Paul-Wheaton
    Bookmark Topic Watch Topic
  • New Topic