It appears that this version of forge requires Java 8.
On my secondary development machine running that java version, forge starts ok.
If this dependency is intentional, it might be a good idea to update the documentation at Documentation | JBoss Forge to indicate that jdk8+ is required.
That's weird. It seems to be a memory setting issue. Forge runs on JDK 7 minimum, although we recommend JDK 8 as JDK 7 is EOL'ed and has a better memory management architecture.
I'll update the docs to recommend JDK 8.
Today I downloaded Forge 2.17.0-Final and observed the same behavior.
The only change I made recently is to install update 51 of java 8.
Forge-2.16.2-Final also would not start.
When i deleted the .forge folder within my windows user directory both forge versions worked immediately.
Apparently something within my .forge profile was preventing forge from starting.
I'm posting this in case anyone else encounters the problem. If anyone knows of a downside to this solution, please post your comments.