Usage Of Garbage Collector In Java?
Feb 21, 2014What is the usage of garbage collector in java.
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Java Beans Usage - Storing Data
Mar 7, 2015I've spent almost 3 hours on googling about java beans and where it is usable. What I've figured out is that a bean has a public non-arg constructor, properties and getters/setters to manipulate them. I also know that a bean contains no logic, only fields. However, I don't fully understand why I need to use beans instead of normal classes even if a class can do the same things like a bean? Are beans used to store data or what?
View Replies View RelatedString Garbage Collection
Jul 22, 2014I have a method
void method(){
String s =null;
String s1 = new String();
}
In this all the two strings are eligible for garbage collection?
Garbage Collection Logs In Application
Nov 26, 2013In my applications garbage collection logs, I see below line.
2013-11-26T10:35:45.050-0500: 5195.298: [GC 5195.298: [DefNew: 17430K->456K(19136K), 0.0102408 secs] 796185K->779211K(2668480K), 0.0103687 secs] [Times: user=0.01 sys=0.00, real=0.01 secs]
2013-11-26T10:36:10.593-0500: 5220.840: [GC 5220.840: [DefNew: 17480K->398K(19136K), 0.0100548 secs] 796235K->779153K(2668480K), 0.0101835 secs]
The last line seems half cut. Does that indicate that there is memory leak in my application? I have not seen the app throwing the out of memory error.
Get Computer CPU Usage?
Apr 7, 2014I want to get current Computer CPU usage of my computer and display it in Console View of Eclipse? How can I achieve this?
My template code is:
Java Code: public class GetCPUUsage{
public static void main(String[] args){
System.out.println("CPU USAGE IS: ??????");
}
} mh_sh_highlight_all('java');
I added ??? as placeholder for CPU usage because I do not know how to retrieve RAM usage by Java.
How To Design - Interface Usage
Jul 17, 2014I have a class as shown below. This class has a method addFilter with 2 parameters (type String and type Command1 )
public class Command1 {
public StringBuffer addFilter(String query, Command1 dataBase) {
//concrete implementation
return query;
}
}
I have another class Command2. Here I need a similar method. The only difference is in the type of parameters passed. (type String and type Command).
public class Command2 {
//TO DO:
public StringBuffer addFilter(String query, Command2 cmd) {
//concrete implementation
return query;
}
}
I have started by using Interface
public interface Helper {
public StringBuffer addFilter(String query, XXXXX parameter2);
}
I would like the classes Command1 and Command2 to implement the interface Helper and override it these two public classes.
However my problem is in dealing with the 2nd parameter. Am I right in my approach? How do I handle this issue?
How To Minimize CPU Usage For Sockets And Threads
Aug 16, 2012I created an instant messenger using java. When I have the Server that communicates between the clients and one client running on my Computer the CPU Usage is at 100%. It really slows down everything else I'm doing and I figure this might be an issue if I gave this to people to use. I don't want the client taking up a lot of CPU Usage if they're just running it in the background while doing other things on their computer. The program utilizes multithreading. Each thread is constantly being polled for input.
The Server, as seen below, has two threads. I explain what the threads do before the code. There is also another while loop running constantly in the server that is waiting for sockets to connect. The loop does not run constantly at the line socket.accept(); it stops and just waits.
The User, split into a menu and chat window, has two threads as well. I explain what the threads do before the code. After I originally posted I put a 100 ms sleep in all my threads. CPU Usage is still at 100%*
This thread listens for input from the user. The input tells the server what action to take. There is a thread running for every user currently connected to the server.
public void run()
{
try
{
input = new DataInputStream(user.getSocket().getInputStream());
output = new DataOutputStream(user.getSocket().getOutputStream());
[code]....
Networking :: Limiting Bandwidth Usage?
Mar 18, 2015I would like to limit my bandwidth usage when accessing/downloading files (similar to the --limit-rate 50K option for curl and wget) as the website has limited bandwidth. I am not exactly sure how to implement this, but I'm guessing it be accomplished via the BufferedReader? I have attached the current code below.
import java.io.OutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
[Code]....
Static Methods Preventing Usage Of Instances?
Jun 17, 2014Declaring the method as static precludes one from using any sort of object oriented programming, thus the method cannot access instance fields of the object if it needs to.
I created two short classes to sort of find out what this meant, but I feel I do not understand it well enough.
Test class (main):
package votek;
public class Test {
public static void main(String[] args) {
SomeMethod();
}
public static void SomeMethod() {
Character character = new Character();
character.totalLevel = 50;
System.out.println(character.totalLevel);
}
}
Character class:
package votek;
public class Character {
private int level = 0;
public Character() {
level = 50;
}
}
OR
Does it mean that making a static method in the class with private instances will prevent the method from using the private instances?
High CPU Usage With Classes Loaded Skyrocketing
May 30, 2014We have a webservices application that uses Java 1.6.0_43, Spring 3.2.3, CXF 2.6.9 and deployed to Jboss 5.0.1 GA in a LINUX x86_64 centos box. It essentially uses apache httpclient (4.2.2) to call internal services and returns the results back to customers. The application has been running fine for a year or so until early this month when all of sudden, it loaded about 300K classes in a very short time during our regression tests and saturated the CPU usage ever since. Hence the application is no longer responding.
I have been trying to troubleshoot the problem for a while. Tried visualvm, dynatrace. thread dumps. heap dumps... None of them is very effective in capturing what are the classes that are loaded so many times and what path triggered that.
EJB / EE :: Design Patterns - Usage Of Transactions And Exceptions
Feb 3, 2015When it comes to Java EE I see many developers having trouble with the usage of transactions and exceptions and when to use what.
I see a full chapter of RESTful Web Services, but do you also relate these Web Services to their counterparts (SOAP Web Services)?
Usage Of Sieve Of Eratosthenes For Finding Primes Faster
Jun 27, 2014I found this method from the same link from which I found the Pandigital method. This method uses the algorithm of sieve of eratosthenes who was a greek mathematician and showed how to find prime numbers by taking an individual number and finding the multiples of it and cut them out for they will not be a prime number. From what I've seen this program gives the results much faster than the traditional way of searching for prime numbers by diving that number by the digits upto half of that number and check for divisiblity.
Well, here's the code
public int[] ESieve(int upperLimit) {
int sieveBound = (int)(upperLimit - 1) / 2;
int upperSqrt = ((int)Math.Sqrt(upperLimit) - 1) / 2;
BitArray PrimeBits = new BitArray(sieveBound + 1, true);
for (int i = 1; i <= upperSqrt; i++) {
if (PrimeBits.Get(i)) {
[Code] .....
As seen from the full program on the site [URL] .... this program was formely writen in C++ and from there I've scrapped out this method as the syntax are corresponding to that of Java, but one problem I faced was in finding the BitArray class in Java. I was unable to understand the approach of this program to find the prime numbers.
Get Current RAM Usage Of Computer And Display It In Console View Of Eclipse?
Apr 7, 2014I want to get current RAM usage of my computer and display it in Console View of Eclipse? How can I achieve this?
View Replies View RelatedAnonymous Object - Can't Understand One Time Usage Of Object
Aug 18, 2014Explain anonymous objects with example clearly...i read some where anonymous objects advantage is saving memory...it is benificiable when there is only one time object usage in our program..i can't understand one time usage of object ....i know anonymous objects but i don't know in which context we use them in our programs...i did the anonymous object program with my own example but i can't differentiate this one with normal object..i'm providing my own example below
//anonymous object
public class anonymous {
int x=10;
int y=25;
void display()
{
System.out.println("anomymous");
[code]....
Why Global Var Initialized With Static Method And Not By Other Static Global Var Declared After Its Usage
Jul 27, 2013Take this:
class test
{
static int i=j;
static int j=10;
.....
this will give illegal forward reference ....
but this will compile successfully ..
class test
{
static int i=test1();
static test1()
{
return 20;
}
}
.....
plz assume we have main method in both cases ..
java would be loading all static members first and would be assigning default values .. and then will be running all the initializers from to bottom ..Why second case is a compile success and not first .. as in second also test1 method is declared after its usage ..
Applets :: Accessing Java Application Without Adding Site To Java Security
Sep 12, 2014I have tried running the java application without adding the site to site list in java security tab. But I get a sand box message as APPLICATION BLOCKED BY SECURITY SETTINGS. How to run the java application without adding the site to site list in java security tab.
View Replies View RelatedCan Use Java Code From OpenScript Or APIs In Separate Java Program?
Oct 24, 2014I want to develop a Java program that uses OpenScript APIs to test my applications. The OpenScript framework automatically creates the Java Code so I was thinking of either using this code or create my own using the APIs.
I tried both options using NetBeans but I'm getting errors everywhere starting with the library import. I'm pretty new to Java so I'm sure I'm missing a lot of things here. I pasted the code below from the OpenScript framework that want to use in a stand-alone file for your reference.,
import oracle.oats.scripting.modules.basic.api.*;
import oracle.oats.scripting.modules.browser.api.*;
import oracle.oats.scripting.modules.functionalTest.api.*;
import oracle.oats.scripting.modules.utilities.api.*;
import oracle.oats.scripting.modules.utilities.api.sql.*;
[Code] ....
Java Application With Several Classes All In Same Java File
Apr 9, 2015I've written a java application with several classes all in the same .java file. It works just fine. Now, I've broken it up so that each class has its own .java file. Still works fine. My next step is to put those classes into a package, but I'm not about to get the program to run.The .java source files are all in /home/user/src
I've set the CLASSPATH to /home/user/src..All of the source files have "package com.myfirm.program" on the first line.I compiled the application with:
javac -d . File1.java File2.java File3.java (etc...)
the compiler created the directory: /home/user/src/com/myfirm/program and put all of the .class files in there.So how do I get the program to run? if I run from /home/usr/src
java File1
I get: Exception in thread "main" java.lang.NoClassDefFoundError: File1 (wrong name: com/myfirm/program/Program)
How To Call Java Methods From Different Java File
Apr 14, 2015I create 2 files:
CircleCalculationMethod.javaMain.java
In Main.java, How can i call method in CircleCalculationMethod.java ?
Should I put everything in same folder ??Should i do something like "import CircleCalculationMethod.java"Should i do something like create a package ...
I use Eclipse software
What Is Difference Between Java SE And Java EE
Sep 19, 2014The title of Question might seem old and previously asked.But I have a Question that what is difference between javaSE and Java EE.Although I knew what comes under JavaSE and What is under JavaEE.But My question is that.
What happens when we add PATH in our Environment Variable How does Eclipse or Other IDE use it?
Second Question is.
For Java SE we declare a Path Variable but for Java EE we do not add any library?(I know we add some jar file like for Servlet(Servlet-api.jar) and for EJB(Ejb.jar),But What is actaul difference?
Odd Even Zero Java
Oct 23, 2014creating a program that will output something like this:
Enter an Integer: 1405302(user inputted)
Your integer contains 2 even digit(s), 3 odd digit(s), and 2 zero(s).
Using Java For Web
Dec 4, 2014I know about coding in general, Java, C, Python, SQL etc. but I barely know anything about making code come together on the web. I have a vague idea about what things like libraries and frameworks are,I'm interested in making a web application with which relies on Java do to the data processing. The idea is that the user inputs some messages, clicks submit, the text is taken away and processed, and the results are displayed on the screen. I would like the UI to be smooth with a modern look and feel.
Also, I usually do programming on Windows but I could also use Linux, so if I'll come across any specific drawbacks using Windows.
Specify WD Where Java App Is Located
Jan 9, 2015How do I specify the Working directory where the Java app is located? It may be different on different machines.
View Replies View RelatedWhat Is Serialization In Java
Apr 8, 2015what is seriazable.But I am not able to come that why it is used and when should I declare my class(Object) as serialzable and when not?
View Replies View RelatedHow To Create API In Java
Aug 9, 2014i need to develop a API in java. that API will be communicate with the some site. Need to import and export the contacts into that site databases.
View Replies View RelatedUTF-8 Conversion In Java?
Oct 30, 2014When I try to convert this value, "Testingu2120" (along with UTF coed u2120)comes as a string as part of SOAP response. I need to convert this UTF-8 characters in to a symbol, in this case it is SM (Service Mark) symbol and show it on the UI.
How can we achieve this in JAVA?
I have four different UTF-8 character set to convert.
TM - u2122
SM -u2120
R - u00AE
C - u00A9