When do you call super() in Java?
I see it in some constructors of the derived class, but isn't the constructors for each of the parent class called automatically? Why would you need to use super?
Has anybody done any benchmarking/evaluation of the popular open-source embedded SQL DBs for performance, particularly write performance? I've some 1:1 comparisons for sqlite, Firebird Embedded, Derby and HSQLDB (others I am missing?) but no across the board comparisons... Also, I'd be interested in the overall developer experience for any of these (for a Java app).
I'm interested in programming languages well suited for embedded programming.
In particular:
Is it possible to program embedded systems in C++?
Or is it better to use pure C?
Or is C++ OK only if some features of the language (e.g. RTTI, exceptions and templates) are excluded?
What about Java in this domain?
Thanks.
i know java API function charAt for example
String s="dato"
char r=s.charAt(0); r is equal d
but my question is how realy it works or what function can i use instead of charAt function to get same result? thanks
Hi,
I have a Cocoon 2.2 based application which uses blocks for different tasks and one block for shared pipeline fragments. All blocks are mounted within an Cocoon webapp.
Now I would like to have an block which generates an overview of all other mounted blocks. I probably will have to use Java code - which is fine - but I am kinda lost where to start.
Can anyone point me the right direction?
How can we generate email failure notice in java if the email is not delivered due to issues like email address does not exists or delivery failure etc.... something like yahoomail notifications
Thanks
I used to be a Java Programmer, which the array need to declare the very first time, like this:
int[] anArray; // declares an array of integers
anArray = new int[10]; // allocates memory for 10 integers
I don't know whether the Objective C , NSMutableArray also give me this ability or not. Actually, I want to make a 10*10 array. thz in advance.
While working in Java, I find it hard to position my Main application window in the very center of the screen when I start the application.
Is there any way I can do that? I tried with some of the predefined methods but none worked.
BTW it doesn't have to be vertically centered, horizontal alignment is the more important goal for me. But vertical alignment is also welcome.
Thanks
how can i write program in java to find the transpose of the graph G, where the input and the output of the program are represented as adjacency list structure.
for example:
input:
12341
outout:
1432
What would the possible scenarios be in which I would get this error produced from a struts web app?
java.lang.IllegalArgumentException: No bean specified
Most people have heard of a Content Management Systems. However, what basic features should an application contain so it can be considered as a true CMS? Also, what Java frameworks could be used to make one?
Hi,
Is there any reason behind using this date as standard for time manipulation? I have seen this standard in Java as well as in Python. These two languages I am aware of. Is other popular languages also follows the same standard?
Please describe.
I am trying to create a Response class in Java which has a method
void setResponse(String response);
Different response subclasses will have different requirements for the response. The string that is passed to the function is received from the user.
What is the correct way of handling a wrong response?
Should the function throw an exception like IllegalResponseException
Should the function be declared like
boolean setResponse(String response, String errorMsg)
and return false if the response is wrong and set the error message to the appropriate value
Hi
I have a header field of 2 bytes where first four bits are packet type and other 12 bits are for length. but i don't know how to store this values and retrieve them.
I am using ms c++ for client and java for server. It is the client which has to set this values and server has to retrieve it.
Thanks
I'm getting a strange NullPointerException, evidently thrown by the following line of code:
Iterator<Note> it = notes.iterator();
I've checked, and at the time the java.util.TreeSet notes is always non-null (with 15 elements). The TreeSet API says nothing about iterator() throwing NullPointerExceptions. What else could be going here?
I was studying the legacy API's in the Java's Collection Framework and I learnt that classes such as Vector and HashTable have been superseded by ArrayList and HashMap.
However still they are NOT deprecated, and deemed as legacy when essentially, deprecation is applied to software features that are superseded and should be avoided, so, I am not sure when is a API deemed legacy and when it is deprecated.
If I have no to little experience in either of them, but know enough Java and Ruby to be comfortable, is one framework harder to learn than the other? Is one easier to use for the beginner on these?
I know it is hard to answer. Just looking for general thoughts on it.
According to the java API, the constructor Date(year, month, day) is depreciated. I know that I can replace it with the following code:
Calendar myCal = Calendar.getInstance();
myCal.set(Calendar.YEAR, theYear);
myCal.set(Calendar.MONTH, theMonth);
myCal.set(Calendar.DAY_OF_MONTH, theDay);
Date theDate = myCal.getTime();
However, I would like something shorter to replace it with (ideally one-two lines).
Any suggestions?
I try to open a large number of files but after 5000 files or so I get
Exception in thread "Main" java.io.IOException: The device is not connected
Is this the expected behavior? Is there a way around it? I want to leave my code as straightforward as possible.
I am trying to create an app which uses a combination of jQuery templates and Backbone.js
I have very little experience in both of them (though I know jQuery)
Could you please provide some good examples where jQuery templates and Backbone.js are used effectively.
Also I am loooking at using JSON for the model/data and trying to persist the data (I use Java at the backend)..So looking for ideas on how that can be integrated?
Thank you.
From the java sources, it look like to drops into native code. Is the cost roughly equivalent to a volatile read or does it need to acquire a lock of some type?
I'm trying to execute a simple example of Multicast sockets on Java.
MulticastSocket s = new MulticastSocket(6789);
InetAddress group = InetAddress.getByName("230.1.1.1");
s.joinGroup(group);
This code generates the error: IP_ADD_MEMBERSHIP failed (out of hardware filters?)
Any idea?
Thanks