How to generate the public key from Digital certificate containing Signature

[colombus]

Hi

I have a .crt file is a Digital Certificate file with a Digital Signature. The signature is obtained by signing the Certificate with a CA private key but to verify the sgnature i require the CA public key which is present in the same .crt file. I am not clear how to generate the public key for verifying the signature. How this can be done in java is my question