I have been told several definitions for it, looked on Wikipedia, but as a beginner to Java I'm still not sure what it means. Anybody fluent in Java and idiot?
Thanks in advance
I have the following interface in Java
public interface IFoo
{
public abstract void foo();
public void bar();
}
What is the difference between foo() and bar()?
When should I use abstract?
Both seem to accomplish what I want unless I'm missing something subtle?
Update Duplicate of Why would one declare a Java interface method as abstract?
My question is related to memory footprint in java for class without data member. Suppose in java I have a class which doesn't have data member and it only contains methods. So if I am creating instance of particular class then does it occupies memory in primary memory except object reference memory ?
What's the reason Java doesn't allow us to do
private T[] elements = new T[initialCapacity];
?
I could understand .NET didn't allow us to do that, as in .NET you have value types that at run-time can have different sizes, but in Java all kinds of T will be object references, thus having the same size(correct me if I'm wrong).
What is the reason?
I'm trying to write a rogue-like game for my blackberry and hopefully
any other phone that supports some sort of JVM.
Because I use Java in my job I'm looking to write the game in another language but I cannot find a language that will work on multiple phones.
Am I stuck with Java?
I'm a big fan of JGraphT, a Java library for graphs. Could anyone recommend a similar Java library for trees? Preferrably FOSS.
What I need is a good API, preferrably typesafe with generics which allows modelling different kinds of trees (with some user data attached to verticies/edges) and run different algorithms and operations on these trees. For instance, traverse or balance.
At the moment I'm not interested in visualization of trees.
We have some portlets created by a team working on a JEE site.
They would like to include one of these portlets within a site I manage, which is ASP.NET.
Aside from solutions like iframes, is it possible to embed a Java portlet within an ASP.NET page?
(Note: I don't have much Java/portlet experience, so please take that into consideration in your answer)
UPDATE
Is this relevant to my question?
http://download.oracle.com/docs/cd/E13174_01/alui/devdoc/docs60/Portlets/Basics/Hello_World_Portlet_NET.htm
Hi, I am looking for a RPC stack that can be used between a Java Server and C++ clients.
My requirements are:
Ease of integration (for both C++ and Java)
Performance, especially number of concurrent connections and response time. Payload are mostly binaries (8-100kb)
I found some like:
http://code.google.com/p/protobuf-socket-rpc/
http://code.google.com/p/netty-protobuf-rpc/
Are there any other good alternatives?
I am torn. I want to start making applications for OS X. There is a specifically under-served market that I would like to tap but I don't know if I should develop it only for the mac with Cocoa and Objective C or if I should develop it with Java and JavaFX.
I guess my question is, is Java robust enough to handle the same things as Objective C on Mac and C# (.net) on Windows?
I have a ResultSet object containing all the rows returned from an sql query.
I want to be able to (in the java code, NOT force it in the SQL) to be able to take a ResultSet and transform it so that it only contains 1 (the first) row.
What would be the way to acheive this? Also, is there another appropriate class (somewhere in java.sql or elsewhere) for storing just a single row rather than trimming my ResultSet?
Thanks!
Hi,
is it possible to return a HashMap to R with the rJava extension of R?
E.g. I have a method in Java, which returns a HashMap and I want this HashMap use in R. I tried:
.jcall(javaObj, "Ljava/util/HashMap", "getDbInfoMap")
This doesn't work.
Do I have to put everything into a String[], that I want to pass to R from Java?
Or is there another possibility?
Any help/info on this would be greatly appreciated.
I'd like to embed code from my SVN repository into my website, using PHP. The SVN has public anonymous access, so the PHP code should be fine reading it.
The code on said SVN is java, and so far I've had no luck finding a syntax-highlighter to make the code more readable. Ideally I'd like one that uses CSS classes so that I can change the colors to match the look of the website.
Could someone point me to a PHP library that highlights Java code?
Hello I have a problem with GregorianCalendar.
What is wrong in there?
How outcome is 2010/6/1 and not 2010/05/31?
package test;
import java.util.Calendar;
import java.util.GregorianCalendar;
public class Main {
public static void main(String[] args) {
Calendar cal = new GregorianCalendar(2010, 5, 31);
System.out.println(cal.get(Calendar.YEAR) + "/" + cal.get(Calendar.MONTH) + "/" + cal.get(Calendar.DAY_OF_MONTH));
}
}
I have a Java application that I run from a console which in turn exec's another Java process. I want to get a thread/heap dump of that child process. On Unix I could do a "kill -3 " but on Windows AFAIK the only way to get a thread dump is Ctrl-Break in the console. But that only gives me the dump of the parent process, not the child. Is there another way to get that heap dump?
I want to implement some attractive /path/to/my/app URLs for a java application. There is already an apache instance in front of the app server, with mod_rewrite installed. Do I win anything by using a java-based rewriter like UrlRewriteFilter instead?
Hi,
I know this question is a bit open but I have been looking at Scala/Lift as an alternative to Java/Spring and I am wonder what are the real advantages that Scala/Lift has over it. From my perspective and experience, Java Annotations and Spring really minimizes the amount of coding that you have to do for an application. Does Scala/Lift improve upon that?
I need to create a SOAP Web Service in C#.
I've done this in the past in Java with eclipse, but couldn't really find something that is SOAP specific when creating a new Web Service project in VS2008.
I need some kind of guidance on how to start this.
Also, the intended client will be implemented in Java,
are there known compatibility issues with this?
Thanks
Suppose I want to add minor syntactic sugars to Java. Just little things like adding regex pattern literals, or perhaps base-2 literals, or multiline strings, etc. Nothing major grammatically (at least for now).
How would one go about doing this?
Do I need to extend the bytecode compiler? (Is that possible?)
Can I write Eclipse plugins to do simple source code transforms before feeding it to the standard Java compiler?
I was asked this question recently during my job interview, and I couldn't answer it. So, what is the most used pattern in java.io and how is it used? What are other patterns used in common java libraries?
One-Liner to list TXT-files.
import java.io.File;
import java.io.FilenameFilter;
...
files = dir.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.toLowerCase().endsWith(".txt");
}
}
);
Source.
Is there an one-liner to list dirs in a dir?
I'm writing a Java application that runs on Linux (using Sun's JDK). It keeps creating /tmp/hsperfdata_username directories, which I would like to prevent. Is there any way to stop java from creating these files?
I'm using Java sockets for client - server application. I have a situation when sometimes client needs to send a byte array (using byteArrayOutputStream) and sometimes it should send a custom java object. How can I read the information from the input stream on the server side and determine what is in the stream so that I can properly process that?