is there difference between classes compiled with java 1.5 and 1.5.0_06

Question

I have compiled a class with java version 1.5.

When i deployed it in the server it gave me bad version error.

If i compile it with java version 1.5.0_06 does that make a difference if the server is having java of version 1.5.0_06

1.Does the last number in version also make the difference??

2.javap -verbose ClassName gives me the minor and major version but how to know with which update the class is compiled with??

Thanks, Sandeep

In an unrelated note: Java 1.5.0_06 is **ANCIENT**. It was release in December 2005! You should update **at least** to the most recent release of Java 5, or you'll have security holes bigger than your average barn door. — Joachim Sauer, Jun 14 '11 at 09:57

score 1 · Answer 1 · answered Jun 14 '11 at 09:38

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The JRE/JDK 1.5.0_06 is an implementation of Java 1.5 (or Java 5, depending on which day of the week it is).

So no, there is no difference, classes compiled for Java 1.5 should work just fine on that version.

The class version won't tell you which update of the JDK the class was compiled with, and that information should also not be relevant.

answered Jun 14 '11 at 09:38

Joachim Sauer

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thanks for the quick reply... but the server is throwing error. I have checked other applications in server with javap and they are showing the same minor: 0 major:49 as my class files also show the same even though it is throwing the bad class version error... – Sandeep Jun 14 '11 at 09:39
Major: 49 would be correct for classes compile by (and/or for) Java 5. – Joachim Sauer Jun 14 '11 at 09:45

score 0 · Answer 2 · answered Jun 14 '11 at 10:23

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Compile a class (any class) with both JDK 1.5 and JDK 1.5.0_06. Then compare the major/minor version of the one compiled with 1.5 with the one compiled with 1.5.0_06. If they were identical, you should be fine running the class compiled with 1.5 on a server that uses Java 1.5.0_06. Otherwise you can not.

answered Jun 14 '11 at 10:23

Behrang

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actually i did wat u said both minor and major versions were same but server throwed error.. i couldnot hav any guesses... strange... – Sandeep Jun 14 '11 at 11:10
@Sandeep: my guess is that you're not deploying what you think you are deploying. – Joachim Sauer Jun 14 '11 at 12:37
@Sandeep: maybe one of the JAR files that your project depends on is compiled with Java 6. – Behrang Jun 15 '11 at 00:54

score 0 · Answer 3 · answered Jun 14 '11 at 12:35

1.Does the last number in version also make the difference??

No. It should not. However, I have faced issues at runtime due to minor version differences. On further investigation, it was found to be due to incomplete understanding of APIs. The developer was expecting obj.getClass().getFields() to return the fields in the order of declaration and it was working that way in one version. In the newer update it was returning the fields in a different order. The API clearly says that "The elements in the array returned are not sorted and are not in any particular order."
Moral of the story: Always develop,test and deploy on the exact same version of Java.

2.javap -verbose ClassName gives me the minor and major version but how to know with which update the class is compiled with??

You cannot. The class file does not even carry that information. See the class-file format: http://en.wikipedia.org/wiki/Java_class_file

The problem that you are getting looks weird. Please post your solution if you get one.

is there difference between classes compiled with java 1.5 and 1.5.0_06

3 Answers3