I want to make a java application software which give the current status/information of the running computer. So, for this, is there any inbuilt/extrnal library present or not?
Can anyone give a simple code which will just. "What is the current status of laptop battery?" or "Is AC adapter is pluged in or not?"
Please help me.
What is the best procedure for storing and retrieving, using native Java serialization, generic objects like ArrayList<String>?
Edit: To clarify. When I serialize an object of type ArrayList<String> I'd like to de-serialize to the same type of object. However, I know of no way to cast back to this generic object without causing warnings.
Hi,
I would like to know if its possible to deploy java class files without restarting JBoss server. I am using jboss v4.2.2.
Also, when I try to deploy jsp files, it works fine and server picks up the changes almost instantly.
Thanks a lot in advance :)
I haven't found many ways to increase the performance of a Java application that does intensive XML processing other than to leverage hardware such as Tarari or Datapower. Does anyone know of any open source ways to accelerate XML parsing?
How to/What is a good library, to create a fading indicator message in Java like that of Outlook when you get a message, or Ubuntu/Gnome when you've connected to a network?
Hi i'm working in task queue concept.... First i struggled to program using task queue and i asked many doubts in stack overflow and Google app engine java. After a search i got a sample program for task queue. http://gaejexperiments.wordpress.com/2009/11/24/episode-10-using-the-task-queue-service/ It will very useful for beginners Like me.
Regards,
Sharun.
Hey guys;
I have a url which leads to in image. How do i grab this image from this url into my servlet? NOTE: the web-app is deployed on google app engine.
java.net.URL myURL = "http://a3.twimg.com/profile_images/150131301/slogo4_normal.jpg";
//code to grab the image
Thank you
Hi,
I'm a beginner in java. I want the logic of the small program.
I have two arrays
array = {a1,a2,a3,a4,a5,,,,,,,,,an}
and
array2 = {b1,b2,b3,b4,,,,,,,,,,,bn}
I want string as:
a1b1,a2a3b2b3,a4a5a6b4b5b6,..........an
Please tell me what will be the logic.
This is simply for fun. This will not be used for any actual encryption. I'm only first year comp sci student and love cryptography.
This took a long time to get working. At approximately N = 18, it begins breaking down. It won't encrypt messages properly after that point. I'm not sure why. Any insights? I'd also appreciate any links you could provide me to tutorials or interesting reading about Cryptography.
import java.math.BigInteger;
import java.security.SecureRandom;
/**
* Cryptography.
*
* Generates public and private keys used in encryption and
* decryption
*
*/
public class RSA
{
private final static BigInteger one = new BigInteger("1");
private final static SecureRandom random = new SecureRandom();
// prime numbers
private BigInteger p;
private BigInteger q;
// modulus
private BigInteger n;
// totient
private BigInteger t;
// public key
private BigInteger e;
// private key
private BigInteger d;
private String cipherText;
/**
* Constructor for objects of class RSA
*/
public RSA(int N)
{
p = BigInteger.probablePrime(N/2, random);
q = BigInteger.probablePrime(N/2, random);
// initialising modulus
n = p.multiply(q);
// initialising t by euclid's totient function (p-1)(q-1)
t = (p.subtract(one)).multiply(q.subtract(one));
// initialising public key ~ 65537 is common public key
e = new BigInteger("65537");
}
public int generatePrivateKey()
{
d = e.modInverse(t);
return d.intValue();
}
public String encrypt(String plainText)
{
String encrypted = "";
int j = 0;
for(int i = 0; i < plainText.length(); i++){
char m = plainText.charAt(i);
BigInteger bi1 = BigInteger.valueOf(m);
BigInteger bi2 = bi1.modPow(e, n);
j = bi2.intValue();
m = (char) j;
encrypted += m;
}
cipherText = encrypted;
return encrypted;
}
public String decrypt()
{
String decrypted = "";
int j = 0;
for(int i = 0; i < cipherText.length(); i++){
char c = cipherText.charAt(i);
BigInteger bi1 = BigInteger.valueOf(c);
BigInteger bi2 = bi1.modPow(d, n);
j = bi2.intValue();
c = (char) j;
decrypted += c;
}
return decrypted;
}
}
I know in Jython you can do
import java.util.Random as Random
Random().nextInt()
But if I have a class I wrote myself, how can I import it into Jython without putting the class itself in a package? If I have a testclass Test:
public class Test {
public void foo() {
System.out.println("bar");
}
}
that's not inside a package. Can I even import that into jython by using something along the lines offrom Test import Test?
I'm using a MySQL database and accessing it through Java.
PreparedStatement prep1 = this.connection.prepareStatement("UPDATE user_table
SET Level = 'Super'
WHERE Username = ?");
prep1.setString(1, username);
The update statement above works fine however I'd like to get the number of rows affected with this statement. Is this possible please?
Basically I want to be able to encrypt and decrypt with AES 256. What is the industry standard library for encryption in Java? Something that has been around a long time and is tried and true.
I have Java Applet(J2EE), I want to make it accessible only to a certain set of users,by authenticating them using username and password.What is the the best way of doing this?
What is the best was to retrieve a file from a server using SFTP (as opposed to FTPS) using Java?
I'll leave the particular definition of best up to you but in my mind it should include free :)
I have created a Java Swing application. It works fine.
I have created application file (.app) for that application using jar bundler.
But the main problem is that my application does not open if I click it on the Dock. I am using Mac OS. How I can launch my application by clicking on Dock
Thanks
Sunil Kumar Sahoo
I've found that java.lang.Ingteger implementation of compareTo method looks as follows:
public int compareTo(Integer anotherInteger) {
int thisVal = this.value;
int anotherVal = anotherInteger.value;
return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1));
}
The question is why use comparison instead of subtraction:
return thisVal - anotherVal;
I have been working with the Swing library for a long time, I'm working on a new project for school and due to the nature of the program it can't look like a generic/boring swing gui. So my question is does anyone know of an interesting java gui library that is not swing or awt?
Hi,
After I read Bloch's discussion http://www.infoq.com/news/2010/04/bloch_java_future
I started to think about "Do I have to switch to scala for new web developements" or is java preferred in all cases. What is your opinion ?
Thanks,
I'm writing an application which monitors the person’s mouse and keyboard. If they have not used the keyboard or mouse for 1 minute, it should pops up a message which says “You have not used the mouse or keyboard for 1 minute” and an OK button.
How do I do this in Java?
Hi,
I would like to open a webpage and run a javascript function from within a java app.
For example I would like to open the page www.mytestpage.com and run the following javascript code:document.getElementById("txtEmail").value="[email protected]";submit();void(0);
This works in a browser...how can I do it programatically?
Thanks!
I have an android app that I am trying to get a file path for a SAX parser. I have the following structure:
assets:(Where my xml file is)
src(same level as assets)
com
msi
androidrss(The calling java file is in here)
I tried several variations of this:
InputSource is = new InputSource("file://../../../../assets/Rss.xml");
But I always get a FNF Exception
Any suggestions?
Thanks
Hello,
In which case should you use primitive types(int) or complex types(Integer)?
Ex:
http://stackoverflow.com/questions/2508918/why-java-compiler-does-not-like-integer-as-type-for-values-in-hashmap this example works with Integer type. Should we always use Integer as a complex type?
Hi all! I'm making an android program that retrieves content of a webpage using HttpURLConnection. I'm new to both Java and Android.
Problem is: Reader reads whole page source, but in the last while iteration it doesn't append to stringBuffer that last part.
Using debbuger I have determined that, in the last loop iteration, string buff is created, but stringBuffer just doesnt append it.
I need to parse retrieved content. Is there any better way to handle the content for parsing than using strings. I've read on numerous other sites that string size in Java is limited only by available heap size. I've tried with StringBuilder too.
Anyone know what could be the problem. Btw feel free to suggest any improvements to the code.
Thanks!
URL u;
try {
u = new URL("http://feeds.timesonline.co.uk/c/32313/f/440134/index.rss");
HttpURLConnection c = (HttpURLConnection) u.openConnection();
c.setRequestProperty("User-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1; .NET CLR 2.0.50727)");
c.setRequestMethod("GET");
c.setDoOutput(true);
c.setReadTimeout(3000);
c.connect();
StringBuffer stringBuffer = new StringBuffer("");
InputStream in = c.getInputStream();
InputStreamReader inp = new InputStreamReader(in);
BufferedReader reader = new BufferedReader(inp);
char[] buffer = new char[3072];
int len1 = 0;
while ( (len1 = reader.read(buffer)) != -1 )
{
String buff = new String(buffer,0,len1);
stringBuffer.append(buff);
}
String stranica = new String(stringBuffer);
c.disconnect();
reader.close();
inp.close();
in.close();
I have database with oracle number type. Could there any possible issues with using java Double when updating table with numeric column. Should i switch BigDecimal or Double is approriate type.
As I fas as I know, BigDecimal is used when arbitrary precision required, when deal with prices for example.
Consider simple API updatePrice(Double d) Should i persist double as is or BigDecimal.valueOf(d) is preferable ?