Rajkamal Pillai

Hello Rob,

Your advice was really helpful.

Playing around with DefaultAlgorithmNameFinder, I ran into the Error -

java.lang.LinkageError: loader constraint violation: when resolving field "id_TA_ECDSA_SHA_1"
the class loader (instance of com/*****/*****/core/server/*****ClassLoader) of the referring class
, org/bouncycastle/asn1/eac/EACObjectIdentifiers, and the class loader (instance of java/net/URLClassLoader) for the field's resolved type
, org/bouncycastle/asn1/ASN1ObjectIdentifier, have different Class objects for that type

Further investigation revealed that there were older versions lying around (1.38, in fact).

Thanks a TON!

Stacktrace:

java.lang.NoSuchFieldError: id_RSASSA_PSS_SHAKE128 at org.bouncycastle.operator.DefaultSignatureNameFinder.<clinit>(Unknown Source) at org.bouncycastle.operator.jcajce.OperatorHelper.<clinit>(Unknown Source) at org.bouncycastle.operator.jcajce.JcaContentSignerBuilder.<init>(Unknown Source) at com.xxxxxx.xxx.broker.ext.command.CreateClientCertificate.invoke(CreateXXXXXXClientCertificate.java:205) at com.xxxxxx.yyyyy.core.cmd.CommandInvoker.invoke(CommandInvoker.java:1275) at com.xxxxxx.yyyyy.core.cmd.CommandInvoker.invokeCommand(CommandInvoker.java:1000) at com.xxxxxx.yyyyy.core.cmd.CommandInvoker.invoke(CommandInvoker.java:969) at com.xxxxxx.yyyyy.remote.servlet.CommandServlet.doPost(CommandServlet.java:217)

Guessing the Algo 'name' has been changed, I checked SHA1WithRSA and SHA256WithRSAEncryption but to no avail.
After going through the documentation I found that all three are still available.

Thank you in advance, Rob!  

Hello,

A security vulnerability has been listed in bouncycastle-1.38 that I am using and have to upgradeto the latest version 1.71

Creating a Certificate signing request -  

JcaPKCS10CertificationRequestBuilder csrBuilder = new JcaPKCS10CertificationRequestBuilder(                               new X500Principal( "...", new String[]{ hostName } )                               , keypair.getPublic()); ContentSigner signer = new JcaContentSignerBuilder("SHA256WithRSA")                               .build(keypair.getPrivate());

Line [4] throws -
java.lang.NoClassDefFoundError: Could not initialize class org.bouncycastle.operator.jcajce.OperatorHelper org.bouncycastle.operator.jcajce.JcaContentSignerBuilder.<init>(Unknown Source)

I have bcprov-jdk15to18-171.jar and bcpkix-jdk15to18-171.jar on CLASSPATH.

What could I be missing here?

Hello,

After a bit of research on how various data structures (Map and Set in particular) are implemented I end up slightly confused.

Map
1. In Java, Map is implemented as a Set.
2. Maps store contents as Entry <Key, Value> objects.

So a Map equates to a Set<Entry<Object, Object>...> with the key object implementing Comparable interface.

Set
1. In Java, Set is implemented as a Map.
2. Each Set element is stored as the key with an Object (placeholder) as the value. Map<Entry<Object,  Object>...>

This appears to be cyclic. I would like some clarity on this.

Cheers,
Rajkamal Pillai.

Hello Peter,

The methods get stored in a Method table.
There would not be optimizations involved with the very first compilation so I would think that the complied code would be loaded in its entirety.
With more number of executions (I have read about an arbitrary number 10K) the JIT would kick in for optimizations and the optimized code would be loaded in the method area.

Cheers.

I had started my journey in Java world using Complete Reference as the starting book. Then I felt I should get more information about the inner details and used Professional Java server programming as my Bible.

These two books have helped me immensely with getting the basics of the language. Now I have around 18 years of experience working with a wide range of applicationframeworks and technologies in the Java space.

All said and done I realize now that no particular book or article is good or bad. There's always some bit of useful information to be gathered from each. The journey has been extremely exciting so long. And it goes on ......

Keep going,
Rajkamal.

class A is visible in package "first" alone as it has default access.
Which means it (class A) would not even be visiblefor class B in package "second".

Doesn't that answer the question?

Ranchers,

I propose creation of a forum for discussion on the latest entry in the world of computing ie, Microservices.

I agree Microservices,  is technology neutral but if knowledge available out here could be put to good use, I say, why not?
What is you opinion?

Cheers.
Rajkamal.

Hello,

I am an experienced Java professional but new to Groovy.
Trying to execute C:\groovy-2.4.0\bin\groovyConsole and face the below error:

C:\groovy-2.4.0\bin>groovyConsole
Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.
The syntax of the command is incorrect.

The JAVA/GROOVY related settings are -
ARIBA_RUNJAVA_USE_JDI=true
JAVA_HOME=C:\devtools\jdk1.6.0_43
JAVA_OPTS=-Xms1024M -Xmx2048M -XX:PermSize=256M -XX:MaxPermSize=512M
GROOVY_HOME=C:\groovy-2.4.0

How can I get around this error?

Thanks,
Rajkamal.

You would need to use JMF for this.
Google should give you all relevant info.

Please take a look at the link below for some details about some answers about GC and fragmentation:
http://publib.boulder.ibm.com/infocenter/javasdk/v1r4m2/index.jsp?topic=%2Fcom.ibm.java.doc.diagnostics.142%2Fhtml%2Fgcfaquestions.html

Thank you Henry Wong, Fred rosenberger and Campbell Ritchie.

Henry: I had missed that the Objects are still accessible via the Collection.

I have read that micro performance management unless working with specific requirements is almost always an overkill and could lead to bad coding styles and less readable code with no real noticeable improvement in performance. Hence the comment.

Thanks again for your replies!

I would think that in the second case "myObject" would be a candidate for GC when the loop exits.
Whereas in the first it would remain 'alive' until after the outer block completes execution.

I would be of the opinion that unless there are really LARGE number of these objects created inside the loop iterations the later versions of Java should be able to optimize the memory/performance effects.

Would anyone like to elaborate, in case I am mistaken?

I am using DNS Java for verifying the domain part in an email address entered by the user.
This was working correctly but now we connect to the internet via a proxy.
Eever since the introduction of the proxy DNS Java fails to connect to the DNS server.
Is there a way to configure DNS Java to use the proxy to connect to the internet?
Logs below:

lookupRecords(google.com. A): Starting lookupRecords(google.com. A): no information found lookup google.com. A unknown Sending to 127.0.0.1:53 Looking for google.com., found -1 Adding google.com. at 12 Looking for com., found -1 Adding com. at 19 28b (UDP write): D8 10 01 00 00 01 00 00 00 00 00 00 06 67 6F 6F 67 6C 65 03 63 6F 6D 00 00 01 00 01 ExtendedResolver: gotjava.net.SocketTimeoutException: Receive timed out Sending to 127.0.0.1:53 Looking for google.com., found -1 Adding google.com. at 12 Looking for com., found -1 Adding com. at 19 28b (UDP write): D8 10 01 00 00 01 00 00 00 00 00 00 06 67 6F 6F 67 6C 65 03 63 6F 6D 00 00 01 00 01 ExtendedResolver: gotjava.net.SocketTimeoutException: Receive timed out Sending to 127.0.0.1:53 Looking for google.com., found -1 Adding google.com. at 12 Looking for com., found -1 Adding com. at 19 28b (UDP write): D8 10 01 00 00 01 00 00 00 00 00 00 06 67 6F 6F 67 6C 65 03 63 6F 6D 00 00 01 00 01 ExtendedResolver: gotjava.net.SocketTimeoutException: Receive timed out lookupRecords(google.com. MX): Starting lookupRecords(google.com. MX): no information found lookup google.com. MX unknown Sending to 127.0.0.1:53 Looking for google.com., found -1 Adding google.com. at 12 Looking for com., found -1 Adding com. at 19 28b (UDP write): 31 37 01 00 00 01 00 00 00 00 00 00 06 67 6F 6F 67 6C 65 03 63 6F 6D 00 00 0F 00 01 ExtendedResolver: gotjava.net.SocketTimeoutException: Receive timed out Sending to 127.0.0.1:53 Looking for google.com., found -1 Adding google.com. at 12 Looking for com., found -1 Adding com. at 19 28b (UDP write): 31 37 01 00 00 01 00 00 00 00 00 00 06 67 6F 6F 67 6C 65 03 63 6F 6D 00 00 0F 00 01 ExtendedResolver: gotjava.net.SocketTimeoutException: Receive timed out Sending to 127.0.0.1:53 Looking for google.com., found -1 Adding google.com. at 12 Looking for com., found -1 Adding com. at 19 28b (UDP write): 31 37 01 00 00 01 00 00 00 00 00 00 06 67 6F 6F 67 6C 65 03 63 6F 6D 00 00 0F 00 01 ExtendedResolver: gotjava.net.SocketTimeoutException: Receive timed out lookupRecords(google.com. A): Starting lookupRecords(google.com. A): no information found lookup google.com. A unknown lookupRecords(google.com. MX): Starting lookupRecords(google.com. MX): no information found lookup google.com. MX unknown

Class.forName() tries to load the class mentioned as argument.
This ClassNotFoundException states that 'java.sql.driver' could not be loaded, as in the class could not be located from the CLASSPATH.