As per documentation: http://docs.oracle.com/javase/8/docs/api/javax/crypto/KeyAgreement.html#generateSecret-byte:A-int-
"If the sharedSecret buffer is too small to hold the result, a ShortBufferException is thrown. In this case, this call should be repeated with a larger output buffer."

It is expected that next call to generateSecret should work.

Refer to the attached test code which fails when JsafeJCE is used, with -

Exception in thread "main" java.lang.IllegalStateException: Secret has not been computed.
at com.rsa.jcm.c.jw.getSecret(Unknown Source)
at com.rsa.cryptoj.c.kk.engineGenerateSecret(Unknown Source)
at com.rsa.cryptoj.c.kk.engineGenerateSecret(Unknown Source)
at javax.crypto.KeyAgreement.generateSecret(KeyAgreement.java:603)
at TestInteropCryptoJ.main(TestInteropCryptoJ.java:125)