[XMLBEANS-612] Adjust Class loading to allow using XMLBeans on Android

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Version 5.0.3
• Fix Version/s: Version 5.1.1
• Assignee: Dominik Stadler
• Reporter: Dominik Stadler
• Created: 14/Jun/22 12:26
• Updated: 14/Jun/22 14:05
• Resolved: 14/Jun/22 14:05

Description

The project https://github.com/centic9/poi-on-android allows to run Apache POI as part of Android Apps and thus also uses XMLBeans.

When trying to update to Apache POI 5.2.2 and XMLBeans 5.1.0, I saw that there is a problem with the Class-loading.

XMLBeans tries to do the following

cl.getResource("xyz.class") 

However on Android you cannot get class-resources this way.

It seems this is only done to prevent a ClassNotFoundException in the call to Class.forName which follows.

 

Therefore I propose to change the code as follows so that we simply expect a ClassNotFoundException instead of doing this separate lookup via getResource()

// BEGIN CHANGES =========================================================================
//
// Simply remove this pre-check and handle ClassNotFoundException below
// as Android does not find .class-files in getResource()
//
// See https://stackoverflow.com/questions/72616517/looking-up-class-files-via-classloader-getresource-on-android
// for a related question
//
/*if (cl.getResource(clName.replace(".", "/") + ".class") == null) {
    // if the first class isn't found in the package, continue with the next package
    break;
}*/

try {
    @SuppressWarnings("unchecked")
    Class<? extends SchemaTypeLoader> cls = (Class<? extends SchemaTypeLoader>) Class.forName(clName, true, cl);
    list.add((SchemaTypeLoader) cls.getDeclaredField("typeSystem").get(null));
} catch (ClassNotFoundException e) {
    // if the first class isn't found in the package, continue with the next package
    // this can happen and thus is ignored here
} catch (Exception e) {
    throw new XmlRuntimeException(e);
}
// END-CHANGES =========================================================================

 

Applying this change locally makes the project work on Android with Apache POI 5.2.2 and XMLBeans 5.1.0.

Issue Links

• is a clone of: XMLBEANS-597 Improve support for using XMLBeans on Android