We've been using the 32bit linux version of the JavaServiceWrapper for quite a while now and it's working perfectly. We are now considering also using it on 64bit linux systems. There are downloads for 64bit binaries on the website, but looking into Makefile for the 64bit version I found the following comment, though: # This makefil...
In Java (or any other language with checked exceptions), when creating your own exception class, how do you decide whether it should be checked or unchecked? My instinct is to say that a checked exception would be called for in cases where the caller might be able to recover in some productive way, where as an unchecked exception would ...
What issues / pitfalls do I need to consider when overriding equals and hashCode in a java class? ...
I've deployed some Managed Beans on WebSphere 6.1 and I've managed to invoke them through a standalone client, but when I try to use the application "jconsole" distributed with the standard JDK can can't make it works. Has anyone achieved to connect the jconsole with WAS 6.1? IBM WebSphere 6.1 it's supossed to support JSR 160 JavaTM Ma...
Every time I create a new project I copy the last project's ant file to the new one and make the appropriate changes (trying at the same time to make it more flexible for the next project). But since I didn't really thought about it at the beginning, the file started to look really ugly. Do you have an Ant template that can be easily po...
I am merging a CVS branch and one of the larger changes is the replacement wherever it occurs of a Singleton pattern with abstract classes that have a static initialisation block and all static methods. Is this something that's worth keeping since it will require merging a lot of conflicts, what sort of situation would I be looking at f...
I'm unsure whether the following code would ensure all conditions given in Comparator's Javadoc. class TotalOrder<T> implements Comparator<T> { public boolean compare(T o1, T o2) { if (o1 == o2 || equal(o1, o2)) return 0; int h1 = System.identityHashCode(o1); int h2 = System.identityHashCode(o2); ...
I want to bring up a file dialog in Java that defaults to the application installation directory. What's the best way to get that information programmatically? ...
I'm trying to find a way to list the (static) dependency requirements of a jar file, in terms of which symbols are required at run time. I can see that the methods exported by classes can be listed using "javap", but there doesn't seem to be an opposite facility to list the 'imports'. Is it possible to do this? This would be similar to...
I'm using ByteBuffers and FileChannels to write binary data to a file. When doing that for big files or successively for multiple files, I get a OutOfMemoryError exception. I've read elsewhere that using Bytebuffers with NIO is broken and should be avoided. Does any of you already faced this kind of problem and found a solution to effici...
If I call finalize on an object from my program code, will the JVM still run the method again when the garbage collector processes this object? This would be an approximate example: MyObject m = new MyObject(); m.finalize(); m = null; System.gc() Would the explicit call to finalize make the JVM's garbage collector not to run the fi...
After reading this question, I was reminded of when I was taught Java and told never to call finalize() or run the garbage collector because "it's a big black box that you never need to worry about". Can someone boil the reasoning for this down to a few sentences? I'm sure I could read a technical report from Sun on this matter, but I th...
What is the most straightforward way to create a hash table (or associative array...) in Java? My google-fu has turned up a couple examples, but is there a standard way to do this? And is there a way to populate the table with a list of key->value pairs without individually calling an add method on the object for each pair? ...
I have a project to build a voting desktop application for a class in Java. While security isn't the focus of the project, I would like to be as realistic as I can. What are some of the primary tools to integrate security into a Java application. Edit: I'm not primarily worried about physical security, we are simply building an applicat...
I'm looking for a good GUI designer for swing in eclipse. My preference is for a free/open-source plugin. ...
I'm working on getting an Introduction to Groovy presentation ready for my local Java User's Group and I've pretty much got it together. What I'd like to see is what you all think I just have to cover. Remember, this is an introductory presentation. Most of the people are experienced Java developers, but I'm pretty sure they have li...
The log4j network adapter sends events as a serialised java object. I would like to be able to capture this object and deserialise it in a different language (python). Is this possible? NOTE The network capturing is easy; its just a TCP socket and reading in a stream. The difficulty is the deserialising part ...
I've taken quite a shine to the Spring Framework and would like to get into it a bit more. I have noticed that aside from plain vanilla JSPs there are various template engines for use with Spring MVC, such as Velocity and Freemarker. Are there others? Which one do you recommend? ...
I have a large codebase without javadoc and I want to run a program to write a skeleton with the basic javadoc information (e.g. for each method's parameter write @param...) so I just have to fill the gaps left. Somebody knows a good solution for this? Edit: JAutodoc is what I was looking for, it has ant tasks, an eclipse plugin and u...
As per my understanding stateless session beans are used to code the business logic. They can not store data in their instance variables because their instance is shared by multiple requests. So they seem to be more like Singleton classes. However the difference is contain creates (or reuses from pool) the separate instance of stateless ...