Trying to verify a signature, Exception thrown: java.io.IOException: Sequence tag error

I'm trying to verify the signature of a message, but I am getting the following exception being thrown.

Exception in thread "main" java.security.SignatureException: Signature encoding error
    at sun.security.rsa.RSASignature.engineVerify(RSASignature.java:185)
    at java.security.Signature$Delegate.engineVerify(Signature.java:1140)
    at java.security.Signature.verify(Signature.java:592)
    ... 4 more
Caused by: java.io.IOException: Sequence tag error
    at sun.security.util.DerInputStream.getSequence(DerInputStream.java:280)
    at sun.security.rsa.RSASignature.decodeSignature(RSASignature.java:209)
    at sun.security.rsa.RSASignature.engineVerify(RSASignature.java:174)
    ... 6 more

Here is my Java code

Signature sig = Signature.getInstance("SHA1withRSA");
sig.initVerify(publicKey);
sig.update(message);
return sig.verify(signature);

publicKey is an instance of JCERSAPublicKey

I read on this website that this error is being caused by the certificate missing the proper header and footer tags (i.e., -----BEGIN CERTIFICATE----- and -----END CERTIFICATE-----). However, I am not using a certificate, but a public key. Looking at my public key PEM file, I can see it has开发者_如何学Go the appropriate headers for a public key.

-----BEGIN PUBLIC KEY-----
...STUFF
...STUFF
...STUFF
...STUFF
...STUFF
...STUFF
-----END PUBLIC KEY-----

A bit odd, because I thought this would have shipped with Java, but there was no Service Provider for the Signature Algorithm. I downloaded BouncyCastle and after adding it as a provider, the code no longer throws up an exception.