I had a problem building/installing ReactionDecoder using maven.
It gave the following error:
Could not find artifact org.openscience.cdk:cdk-bundle:jar:2.4-SNAPSHOT
Version 2.4 does not seem to be available at https://search.maven.org/artifact/org.openscience.cdk/cdk-bundle, but 2.3 and 2.5 are.
I edited the poml.xml file to point at 2.5 instead; i.e. I replaced "2.4-SNAPSHOT" with "2.5".
That seemed to resolve that particular issue (but I still have others!)