With this application you'll be able to know all the Japanese language characters. You will be able to see their shape, meaning, and other similar features. ZKanji is, above all, an English-Japanese and vice versa dictionary, so that you'll be able to write a word in English and see the corresponding word in Japanese.
ZKanji also has a tool to be able to check what you have learnt. You will see sentences written in Japanese and you'll have to write the translation into English.
If you're interested in learning Japanese, a good way to start is by downloading ZKanji and getting familiarized with its characteristics and meanings.