Since ASDM 7.12(2) I am no longer able to run ASDM on CentOS 7 using javaws. It appears to launch and dies. However, I am now running ASDM directly in java and it works fine.
First attempt "javaws https://<ip of firewall>/admin/public/asdm.jnlp"
After the launch fails, find the cached jar files. Use "locate asdm.jnlp" to find where they are cached.
Copy the files to a know location and change to that directory. Then issue:
java -classpath lzma.jar:jploader.jar:dm-launcher.jar:retroweaver-rt-2.0.jar com.cisco.launcher.Launcher
and ASDM will start.
If you have a high DPI monitor adding the "-Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel" flag to the java command may help with the tiny fonts.