َUPDATE:
My target: I'm going to build Zekr software with new library in Debian Repository.Already Zekr was in old debian repo.
Now, I have an old code written by java and I compile and run it under JDK11 and new version of dependencies library via ant clean;ant compile;ant run
Then I get the following errors:

org.eclipse.swt.SWTError: No more handles [MOZILLA_FIVE_HOME='/usr/lib/firefox'] (java.lang.UnsatisfiedLinkError: Could not load SWT library. Reasons: 
    no swt-mozilla-gtk-4233 in java.library.path: [lib]
    no swt-mozilla-gtk in java.library.path: [lib]
    /home/mohsen/.swt/lib/linux/x86_64/libswt-mozilla-gtk-4233.so: libxpcom.so: cannot open shared object file: No such file or directory
    Can't load library: /home/mohsen/.swt/lib/linux/x86_64/libswt-mozilla-gtk.so
)

At first you have to change line 92, attribute source and target to 1.6 , and at same line add includeantruntime="false" Then in javac directive, add <compilerarg value="-Xlint:-options"/>
The given code uses SWT library. How can I solve it?
How can I tell to build.xml to use new version of my libs?

By the way, Debian removed xulrunner from their packages.