I am making some revisions from the lecture slides and it says a constructor is executed in the following way: If the constructor starts with this, recursively execute the indicated constructor, then go to step 4. Invoke the explicitly or implicitly indicated superclass constructor (unless this class is java.…
How do I programmatically compile and instantiate a Java class?
I have the class name stored in a property file. I know that the classes store will implement IDynamicLoad. How do I instantiate the class dynamically? Right now I have Does the newInstance only load compiled .class files? How do I load a Java Class that is not compiled? Answer How do I load a Java Class that…
Why do people use bouncycastle instead of Java’s built in JCE provider? What is the difference?
Why do people use bouncycastle instead of Java Cryptography Extension? What is the difference? Answer BouncyCastle has many more cipher suites and algorithms than the default JCE provided by Sun. In addition to that, BouncyCastle has lots of utilities for reading arcane formats like PEM and ASN.1 that no sane…
Checking for a null int value from a Java ResultSet
In Java I’m trying to test for a null value, from a ResultSet, where the column is being cast to a primitive int type. From the code fragment above, is there a better way to do this, and I assume that the second wasNull() test is redundant? Educate us, and Thanks Answer The default for ResultSet.getInt …
How to extract CN from X509Certificate in Java?
I am using a SslServerSocket and client certificates and want to extract the CN from the SubjectDN from the client’s X509Certificate. At the moment I call cert.getSubjectX500Principal().getName() but this of course gives me the total formatted DN of the client. For some reason I am just interested in th…
Can we start the maven build from the point where it failed
Suppose, I am doing a full build on my large project which has 7 modules and on the 6th module, the build failed because a test failed. Is there any way by which I can start the build from the point …
How to set application name with JPA (EclipseLink)?
hello everybody i am using JPA with EclipseLink and oracle as DB and i need to set the property v$session of jdbc4 it allows to set an identification name to the application for auditing purposes but i had no lucky setting it up….i have been trying through entitiyManager following the example in this pa…
Exporting Eclipse project with a reference to native library
I have an Eclipse project, that uses JMF, I found out I could skip the JMF installation process and still to use the CaptureDeviceManager of the JMF, and to receive the list of devices if I could point my project to the native lib of the JMF. I’ve managed to add the native lib to the IDE run/debug, but …
Java – Collections.sort() performance
I’m using Collections.sort() to sort a LinkedList whose elements implements Comparable interface, so they are sorted in a natural order. In the javadoc documentation its said this method uses mergesort algorithm which has n*log(n) performance. My question is if there is a more efficient algorithm to sor…
Is it possible to add JPA annotation to superclass instance variables?
I am creating entities that are the same for two different tables. In order do table mappings etc. different for the two entities but only have the rest of the code in one place – an abstract superclass. The best thing would be to be able to annotate generic stuff such as column names (since the will be…