String servicePrincipal = KerberosTestUtils.getServerPrincipal();
GSSName serviceName = gssManager.createName(servicePrincipal, GSSUtil.NT_GSS_KRB5_PRINCIPAL);
gssContext = gssManager.createContext(serviceName, GSSUtil.GSS_KRB5_MECH_OID, null,
GSSContext.DEFAULT_LIFETIME);
gssContext.requestCredDeleg(true);
gssContext.requestMutualAuth(true);
byte[] inToken = new byte[0];
byte[] outToken = gssContext.initSecContext(inToken, 0, inToken.length);
Base64 base64 = new Base64(0);
return base64.encodeToString(outToken);