On 25 Sep, Don Lewis wrote:
> On 24 Sep, Don Lewis wrote:
>> I've been looking into the problem where AOO418 can't detect older
>> versions of java when it is built with a new version of java. This is a
>> definite puzzle because the detection is done by the jvmfwk module, and
>> the code in that module is identical between AOO418 and trunk. The only
>> difference is that this module has been changed from dmake to gbuild in
>> trunk.
>>
>> The way that java detection works is that we scan the possible java
>> locations, and for each we run
>> [path to javaa]/java[.exe] -classpath C:\\Program\ Files\\OpenOffice\
>> 4\\program JREProperties
>> which is supposed to output a bunch of data about that version of java,
>> which we read and parse. If that fails, then we decide that version of
>> java is invalid or broken.
>>
>> When I build AOO418 with Java 8 and it tries to detect Java 7, I see
>> this stack trace sent to stderr:
>>
>> java.lang.UnsupportedClassVersionError: JREProperties : Unsupported
>> major.minor version 52.0
>> at java.lang.ClassLoader.defineClass1(Native Method)
>> at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
>> at
>> java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
>> at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
>> at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
>> at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
>> at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
>> at java.security.AccessController.doPrivileged(Native Method)
>> at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
>> at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
>> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
>> at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
>> at
>> sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
>> Exception in thread "main"
>>
>> The problem is that the JREProperties was compiled with Java 8, which
>> Java 7 can't use:
>> $ file /cygdrive/c/Program\ Files/OpenOffice\ 4/program/JREProperties.class
>> /cygdrive/c/Program Files/OpenOffice 4/program/JREProperties.class: compiled
>> Java class data, version 52.0 (Java 1.8)
>>
>> If I build trunk with Java 8, I see:
>> $ file /cygdrive/c/Program\ Files/OpenOffice\ 4/program/JREProperties.class
>> /cygdrive/c/Program Files/OpenOffice 4/program/JREProperties.class: compiled
>> Java class data, version 51.0 (Java 1.7)
>> That's why we don't see this issue with trunk
>>
>> It is possible to use a new java compiler to build for older versions of
>> java using the --target option, but I don't see any sign that we are
>> doing so.
>>
>> Unfortunately the build is too silent for me to see what is actually
>> happening during the build. My suspicion is that somehow the trunk
>> build is somehow using Java 7 to build.
>
> I finally figured out the difference. The 4.1.x build uses the selected
> javac to build the .class file, whereas trunk and 42X use ant, and
> solenv/ant/aoo-ant.xml (new to trunk ant 42X) says:
> <property name="java.baseline.version" value="1.7"/>
>
>> I see two paths forward. The first is to build with the oldest version
>> of java that one might want to use, which is the status quo. The second
>> is to somehow pass the --target option to specify an older java version
>> for compatibility.
>
> We could also cherry-pick the jvmfwk conversion to gbuild and the other
> changes for ant.
Even simpler, there is a JAVAFLAGS variable used by the dmake build.
Configure sets it:
JAVAFLAGS="-source 1.5 -target 1.5"
for Eclipse Java Compiler, but otherwise leaves it unset.
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