apkpatch.jar工具中，类DexDiffer可能有误

```
public DiffInfo diff(File newFile, File oldFile) throws IOException {
...
boolean contains = false;
for (DexBackedClassDef newClazz : newDexFile.getClasses()) {
for (DexBackedClassDef oldClazz : oldDexFile.getClasses()) {
if (newClazz.equals(oldClazz)) {
compareField(newClazz, oldClazz, info);
compareMethod(newClazz, oldClazz, info);
contains = true;
break;
}
}
if (!contains) {
info.addAddedClasses(newClazz);
}
}
return info;
}
```

如果contains第一次变为true，`info.addAddedClasses(newClazz);`就再也得不到执行。应该将`boolean contains = false;`移动到第一个for块里面。

Start at the DexDiffer.diff entry point in the apkpatch.jar tool and inspect how the contains flag is scoped across new classes. Verify the behavior with a diff containing multiple new classes, ensuring each class is classified independently and all added classes are reported.

Written by the indexing model from the issue text.