sir actually i wana check that the barcode i have generated are valid or not... i dont have barcode reader and i just want a simulation of that.
Simplest way to check actual barcodes without a reader is to find a barcode generation service--like the one Killer_Typo suggested--for the barcode symbology you're implementing (e.g. UPC, EAN). Then put the same numbers into both your program and the generator service and see if they come out the same. Of course, this only works if you trust the third-party barcode generator.
If all you're checking is that the numbers fit the barcode scheme (e.g. checksums are correct), you're really just checking that you've actually implemented the algorithm correctly. Try working through the algorithm by hand for a few sets of numbers to see if your program comes up with the same thing. Even better, find a few real barcodes and check those against what your program does with them.
you can try java barcode reader library which is a pure java library to recognize barcode data from barcode images. and it supports more than 20 linear and 2d barcode types. i think you can use it to verify your generated barcode image is right or not.