The constructor SignedObject(Serializable,PrivateKey,Signature) throws ProviderException in case when PrivateKey and Signature parameters are created using provider "SunPKCS11-Solaris".

Please see the minitest and it's output:
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import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignedObject;

public class SignatureMinitest {
  public static void main(String[] args) throws Exception {
    String provider = "SunPKCS11-Solaris";
    Signature sig = Signature.getInstance("SHA384withRSA", provider);
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA", provider);
    kpg.initialize(512);
    KeyPair kp = kpg.generateKeyPair();
    PrivateKey privKey = kp.getPrivate();
    PublicKey pubKey = kp.getPublic();

    sig.initSign(privKey);
    new SignedObject("Test string for getSignature test.", privKey, sig);
  }
}

Exception in thread "main" java.security.ProviderException: sun.security.pkcs11.wrapper.PKCS11Exception: CKR_DATA_LEN_RANGE
        at sun.security.pkcs11.P11Signature.engineSign(P11Signature.java:483)
        at java.security.Signature$Delegate.engineSign(Signature.java:1128)
        at java.security.Signature.sign(Signature.java:522)
        at java.security.SignedObject.sign(SignedObject.java:227)
        at java.security.SignedObject.<init>(SignedObject.java:144)
        at SignatureMinitest.main(SignatureMinitest.java:20)
Caused by: sun.security.pkcs11.wrapper.PKCS11Exception: CKR_DATA_LEN_RANGE
        at sun.security.pkcs11.wrapper.PKCS11.C_Sign(Native Method)
        at sun.security.pkcs11.P11Signature.engineSign(P11Signature.java:474)
        ... 5 more
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Possibly the root cause is the key length, because the same code with provider "SunRsaSign" produces InvalidKeyException:

Exception in thread "main" java.security.InvalidKeyException: Key is too short for this signature algorithm
        at sun.security.rsa.RSASignature.initCommon(RSASignature.java:111)
        at sun.security.rsa.RSASignature.engineInitSign(RSASignature.java:93)
        at sun.security.rsa.RSASignature.engineInitSign(RSASignature.java:84)
        at java.security.Signature$Delegate.engineInitSign(Signature.java:1095)
        at java.security.Signature.initSign(Signature.java:480)
        at SignatureMinitest.main(SignatureMinitest.java:19)