Java DICOM viewer fails on MacOS Catalania (10.15.3)
These warnings are caused by Oracle tightening security in the JVM (which is unfortunately badly needed) but currently does not cause the process to crash.   

Hence my guess is that something else has broken.  Without anything further to go on, I would guess (based on the exit code 13) that the Java DICOM viewer is 1) rather old and 2) links in native code, notably Java 6 (perhaps even 5) and native 32-bit library.

Unfortunately for you, modern Java versions are 64-bit only, and cannot use 32-bit libraries, so if I'm right the Java you have now will not run this program.  You might, however, have luck in getting the old Java 6 from Apple and use that instead, but only if you have not upgraded to Catalina.

I would look around for a newer version of the DICOM viewer on the net.  You might be lucky.