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From Thomas Nielsen <Thomas.Niel...@Sun.COM>
Subject Re: [VOTE] Require Java 5 (or later) compiler to build Derby
Date Wed, 10 Oct 2007 07:51:15 GMT
Dag H. Wanvik wrote:
> It seems -target jsr14 is not officially supported for the Sun JDK, at least it is not
> listed in the javac documentation as a valid target:
> 
> http://java.sun.com/j2se/1.5.0/docs/tooldocs/solaris/javac.html#options

True.

 From what I can tell -target jsr14 was introduced during generics 
development in 1.5 beta, and is not officially supported nor documented 
It still works though, but we probably shouldn't rely on it as it may 
probably change without notice.

--- snip ---
<5>derby/tests> javac -version
javac 1.5.0_12
...

<5>derby/tests> javac -source 1.5 -target jsr14 SqlStressTest.java
<5>derby/tests>
--- snip ---

This short article on the IBM site is actually a good writeup on this 
topic by a Suns Brian Goetz:
http://www.ibm.com/developerworks/java/library/j-jtp02277.html

To summarize: -target jsr14 gives you the following on a pre-java 5 JVM:
- generics
- autoboxing
- for-each loops (with some limitations)
- String concatenation using StringBuffer, not StringBuilder

If your interested in more details - please refer to the article. It has 
some additional information on Retroweaver and Retrotranslator as well.

Thomas
-- 
Thomas Nielsen

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