People please let me know what is the exact difference between JDK 6 and J2SDK. Guess both of these installations belong to Java 2.

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Hi,

This is due to Sun's naming convention changing as they progressively bring Java into a wider and stabler platform.
To follow the history :
- The first releases of Java in the early 90's was labeled 1.0 , then 1.1. We talked then about a JRE 1.1 and JDK 1.1 , for Java Runtime Environment and Java Development Kit.
- When it came to Java 1.2 , changes were so radical that the brand name for Java platform 1.2 was 'Java 2'. The JRE and JDK then became J2RE 1.2 and J2SDK 1.2 ! (for "Java 2 Software Development Kit, version 1.2"). This was the beginning of a little confusion...
- This continued like that until version 1.4.x.
- When introducing platform 1.5.0, Sun thought it a little weird to always stick to a '1.x' version number, even for major changes, like in 1.2. This made people think that version 1.5.0 was merely an update to version 1.0, where I beleive not a single line of code has survived... they then decided to drop the initial '1', and to call the new version 5.0 instead of 1.5.0. However, 1.5.0 would also remain for technical compatibility reasons. Version "5.0" is the product version, while "1.5.0" is the developer version, and the whole still being labeled as 'Java 2' !! We then had a 'J2SE 5.0' for the name of the platform, the runtime and development kit being now reverted to JRE 5.0 and JDK 5.0 (instead of J2SDK and J2RE) due to developer popularity.
- For platform 1.6, Sun then dropped the last digit, to call it 'Java 6' , and dropped the 'Java 2' concept. The platform is now called 'Java SE 6', with a 'JDK 6' and a 'JRE 6'. Note that the 'developer version' is still 1.6.0, this is what you would get from doing java -version, and the name of the installation directory...

But, to answer precisely to your question :
- JDK 6 is the Java Development Kit for Java Platform 6 (developer version 1.6.0)
- J2SDK is a Java Development Kit for an unspecified version, there should be an additional version right after. However, if it is really called 'J2SDK', it should technicaly mean that it is comprised between 1.2.x and 1.4.x, but as everybody is confused, this is not a guarantee...

Hope this helps

Antoine

 

 

 

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