The choice depends on what you want your company to achieve with the project. Do you want to get the job done quickly, effectively and at an agreed to price? Then the answer is use perl, document well, collect your payment and be sure to ask if you can use them as a reference as a satisfied customer.

On the other hand you mentioned that this is a government contract job. In such a situation do you want to ride the Java gravy train of no foreseeable code freeze? Do you want to charge your client to do various web searches for regular expression and printf() replacement libraries? Do you want to re-write most things again and again as the political bickering within you and your client's organization draws the project out longer and longer and ...

Such bloatware is the key to financial success. Just look at IBM and Microsoft today.