BouncyCastle ECDH Key Agreement Fails

BouncyCastle ECDH Key Agreement Fails

I implemented a Elliptic Curve Diffie Hellman cryptography using
BouncyCastle API. But, it doesn't seem that the key agreement is working
properly. It prints false.
Where did I do wrong? Thank you.
ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("B-571");
KeyPairGenerator g = KeyPairGenerator.getInstance("ECDH", "BC");
g.initialize(ecSpec, new SecureRandom());
KeyPair aKeyPair = g.generateKeyPair();
KeyAgreement aKeyAgree = KeyAgreement.getInstance("ECDH", "BC");
aKeyAgree.init(aKeyPair.getPrivate());
KeyPair bKeyPair = g.generateKeyPair();
KeyAgreement bKeyAgree = KeyAgreement.getInstance("ECDH", "BC");
bKeyAgree.init(bKeyPair.getPrivate());
//
// agreement
//
aKeyAgree.doPhase(bKeyPair.getPublic(), true);
bKeyAgree.doPhase(aKeyPair.getPublic(), true);
byte[] aSecret = aKeyAgree.generateSecret();
byte[] bSecret = bKeyAgree.generateSecret();
System.out.println(aSecret);
System.out.println(bSecret);
if (aSecret.equals(bSecret)){
return true;
} else { return false; }