make code compatible with java 11

changed milestone to %v14.0.0~alpha.0

added enhancement label

created merge request !777 (merged) to address this issue

mentioned in merge request !777 (merged)

closed via merge request !777 (merged)

mentioned in commit 50415957

reopened

the project compiles but there are errors:

• coverage report is not shown
• unit tests for rest, reactome, sbgnml, cellDEsigner-plugin, sbml, celldesigner-converter are failing

created merge request !862 (merged) to address this issue

mentioned in merge request !862 (merged)

closed via merge request !862 (merged)

mentioned in commit fb9e7610