Fuad Abinader

Hi all,

I'm having the following problem using my own ClassLoader.
Basically I need to dynamically load classes contained inside a JAR files, so I followed instructions for creating my own class loader. I did it, and after some problems, now I'm loading the classes through my own class loader.
The problem is that after releasing all references for my own class loader, it is still possible to load the classes from the JAR file even that the classloader in which the classes were resolved seems to be garbage-collected.
Does anybody know how to re-resolve a class? Or how to probide a solution to this problem?

Regards,

Fuad Abinader

Sorry, I didn't explain the case correctly: I don't want to obtain the original value that the SHA-1 digest represents, but the digest value itself which is coded on a RSA signature. I mean, I have this encrypted value (the RSA signature) which was generated based on a value (the SHA-1 digest value), and from the public key and the encrypted value, I want to obtain back the decrypted value. Any hints on how to do that?

Also, I'm having problems ensuring the validity of the signature value against the certificate. I'm using the following code:
public boolean verifySignature(byte[] certificate, byte[] signature) throws CertificateException, InvalidKeyException, SignatureException { X509Certificate x509Certificate = null; ByteArrayInputStream bais = new ByteArrayInputStream(certificate); while (bais.available() > 0) { x509Certificate = (X509Certificate) this.certificateFactory.generateCertificate(bais); } try { bais.close(); } catch (IOException ioe) { ioe.printStackTrace(); } x509Certificate.checkValidity(); this.signatureVerifier.initVerify(x509Certificate); return this.signatureVerifier.verify(signature); }
, but this always return false, no matter if the signature is valid against the certificate or not. Any hints on that too?

Regards,

Fuad Abinader

Hi all,

I'm trying to extract the SHA-1 digest from a SHA1withRSA signature value. Given that I have the X.509 certificate, which means that I can extract the X.509 public key, and given that I have the signature value, computed using RSA over the SHA-1 digest value, how can I extract back the SHA-1 digest value?

Regards,

Fuad Abinader

Hi all,

Well, the problem is that I'm trying to create a J2ME emulator, and for that, I'm using J2SE API to provide J2ME services in the way the J2ME API specifies. For that, I'm making a wrapper for HTTP, in a way that I use a J2SE HttpURLConnection to simulate the behavior of a J2ME HttpConnection. The problem is that they have different behavior regarding methods that cause the transition to the connected state, and also they behave differently on when to return exceptions.
For example, in J2ME, if I open a HTTP connection, and call connection.getDate(), this causes the connection to go to the connected state; therefore, if I call the method connection.setRequestProperty(), this method should throw an IOException, because the connection will be at the connected state. If I do the same on a instance of J2SE HttpURLConnection, no exception is thrown. Therefore I have to check if the connection is in the connected state in order to return the IOException.
Can anyone help me on this issue? Any hints?

Regards,

Fuad Abinader

Hi all,

I'm working on a university project to create a J2ME emulator, using J2SE API. Therefore, in order to allow HTTP connections to J2ME applications, I'm using a HttpURLConnection from the J2SE API. However I'm stucked with it, because I have to check if the HttpURLConnection instance is in the connected state, but there is no method available to return it. Does anyone knows if there is a way to know that?

Thanks in advance,

Fuad Abinader

Fuad Abinader
Brazil
28

Hi all,
I think questions 6 and 7 are wrong. According to MIDP 2.0 specification, page 442, mandatory attributes for JAD are:
- MIDlet-Name
- MIDlet-Version
- MIDlet-Vendor
- MIDlet-Jar-URL
- MIDlet-Jar-Size
, and the optional are:
- MIDlet-<n> for each MIDlet
- MicroEdition-Profile
- MicroEdition-Configuration
- MIDlet-Description
- MIDlet-Icon
- MIDlet-Info-URL
- MIDlet-Data-Size
- MIDlet-Permissions
- MIDlet-Permissions-Opt
- MIDlet-Push-<n>
- MIDlet-Install-Notify
- MIDlet-Delete-Notify
Therefore, I think the answers to questions 6 should be D and E, and for question 7 should be A, B and E.
Best regards,
Fuad Abinader

Hi all,
Looking at CLDC 1.0, it is said nominally that JNI and reflection were features removed from JVM. However, on CLDC 1.1, these two are not listed on the removed features. Does anyone here knows if these features were really added? Or it was just a problem with CDLC 1.1 docs?
Best regards,
Fuad Abinader