I have worked on coding parsers in many languages, including java. Without seeing the exact EBNF definition for your language it is difficult to know exactly how long the project will take. However assuming that the language is somewhat simple, and noting your urgency, I believe that I will be able to finish in 1 day.
Depending on your requirements, I would approach the project either using CUP to generate the parser and symbol table, or by hand coding the parsing of each production as a function.
Please contact me if you want any clarification on my strategy for your project, or the time frame that I have estimated.