Heap Dump Generated With Read-write Permissions For Java Process Owner
Apr 14, 2014
I have a question regarding the permissions set for generated heap dumps.
I have some Jetty servers running on Linux (Java 6 64 bit / Java 7 64 bit) with the following Java arguments:
-XX:+HeapDumpOnOutOfMemoryError
-XX:HeapDumpPath=/opt/apps/heapdump
When there is a out-of-memory exception a heap dump is automatically generated by the JVM. But it seems that the heap dump permisions are set to read-write for owner only (600).
When I create files then they have by default read-write for owner and group/all read access (644).
$ ls -l
total 795432
-rw------- 1 bamboop bamboo 811322265 Apr 14 09:18 java_pid337.hprof
-rw-r--r-- 1 bamboop bamboo 6 Apr 14 12:57 test
Here the umask set for the server running the Java processes
$ umask
0022
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Oct 12, 2013
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Nov 4, 2014
I created a main class called X and two Y and Z classes.
Y and Z implements Runnable classes.
class X contains a static array A that can be accessed in Y and Z.
The Run () method of the class Y reads an input file and populates the vector A.
The Run () method of the Z class uses data stored into the vector A to process some data.
The objective of using threads in this problem is: as the vector A is filled in the Run () method of class Y, the Run () method of the class Z will processing the received values in the vector A.
to do this I did the following calls in the main method of class X:
ObjectY y = new Y ();
Thready thread = new Thread (objectY);
threadY.start ();
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threadZ.start ();
is that correct? I'm getting the expected results, but dont know if the code is parallelized in fact.
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Oct 10, 2014
Ex. If I type 5943, the program will say
mill = 5
hun = 9
ten = 4
uni = 3
get the picture I had to translate the decimal value names from a different language.
This is what I have tried...,
Java Code:
import java.util.Scanner;//Permite el uso de leer el teclado del usuario
public class DeterminarValorDecimal//Nombra el documento
{
public static void main(String [] args)//Podemos ver la clase
{
[Code].....
But what this does is I have to enter the single digits one by one. I want to be able to type the whole number. Is there a method that reads the length of the whole number and lets me classify each digit so I can do what I want to do?
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Feb 18, 2015
I want to disable the read write execute permissions for the users on C:/ drive. i.e. to disable their Administrator rights. How can I do it using Java?
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May 21, 2013
JFrame frame = new JFrame();
frame.setIcon("aaa.ico");
JDilaog dialog = new JDialg(frame, "dialog" , true);
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Mar 1, 2015
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Nov 21, 2013
I am using a 64 bit Win 7 Pc with 64-bit JVM and we get the error: Java heap space. So we want to increase the Java heap size but not for one application but for every application or in general.
We tried with the java -xmx command but it didn't work...
We tried setting the system variable JAVA_OPTS but again it didn't work...
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Feb 4, 2014
I am trying to do a read/write int property called currentQuestionIndex. This property is the index of the question currently selected, and the value of the property is 0 when a DrivingTest object is first created. I dont understand how to do this. I am not sure how to get the index of the current question. i was trying to use an iterator but i dont think i was doin it right. My question class that hold all my data
package cs320Labs.servlet;
public class Question {
String description;
String answerA;
String answerB;
String answerC;
int correctAnswer;
[Code] ....
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Mar 17, 2014
I have a question for the read and write method in file.In my code for writing i m using PrintWriter and for reading Scanner.So i m saving data to file and when is need it i m reading from the file.but i also have to delete specific data from it.Is there a way to delete a specific line from the file?When i google my problem i found that is better to save your data to temporary file and then to the final.
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Jun 4, 2014
I want to read and write json to/from a file. I read the following document:
JsonReader (Java(TM) EE 7 Specification APIs)
I try to define a JsonReader object in Eclipse:
JsonReader jr
But there appears to be no import for it. Where I am supposed to get the Json library?
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Oct 17, 2014
I'm rather new to programming and I'm trying to make a gui program that will allow the user to create text files. They will be prompted to enter what they'd like to save their file as and then they will be allowed to input text to that file . They will also be allowed to open their files to modify or view its contents. So to start things off, I'm making a prototype if you will.. I've been able to save to a file the problem occurs when I try to read/display it.
Main Class:
public class MainActivity {
public static void main(String[] args) {
// Access to other classes
WriteFile writer = new WriteFile();
ReadFile reader = new ReadFile();
[Code] ....
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Apr 15, 2015
To read or write to a USB device must use an external library?
Such as this? usb4java - About
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Jul 25, 2013
My background is mainframe and i'm new to java. We're moving from mainframe to the java world and I'm trying to achieve a task. I have a main folder and then bunch of sub folders and each sub folder has bunch of xml files, files size are varies some of them are 900kb. I need to read these xml files and send the output to the txt file (comma separated).
Some possible options or sample example... Please find below the sample xml file. I need to extract information's only where
FORM name="F00001".
[CODE]<PACKET>
<FORM name="F00001" sequence="0">
<FIELD sequence="1">02</FIELD>
<FIELD sequence="2">00000</FIELD>
<FIELD sequence="3">CAB100</FIELD>
<FIELD sequence="4">TEFAP001</FIELD>
<FIELD sequence="5">EMPTY FIELD</FIELD>
<FIELD sequence="6">009.999.989</FIELD>
[Code] .....
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Jun 21, 2014
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This is what I ran : xml2csv-conv data.xml data.csv
Error:
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at com.sun.org.apache.xerces.internal.dom.DeferredDoc umentImpl.createChunk(Unknown Source)
at com.sun.org.apache.xerces.internal.dom.DeferredDoc umentImpl.ensureCapacity(Unknown Source)
at com.sun.org.apache.xerces.internal.dom.DeferredDoc umentImpl.createNode(Unknown Source)
at com.sun.org.apache.xerces.internal.dom.DeferredDoc umentImpl.createDeferredTextNode(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.Abstrac tDOMParser.character
[code]....
Additional information: I am running this from a Windows8 64 bit machine with 8GB physical RAM.
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When I go to the method again the ID will be added so if I input UK, the file will contain:
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2:UK
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1:USA
2:UK
3:Norway
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1:USA
3:Norway
I'm quite new to Java, I'm in a Java course since soon 3 weeks back and I have sure learned a lot, all the loops and basic statements that exist in most languages, but now when it comes to this I just don't understand.
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Apr 21, 2014
I got a question in my last interview, its all about multithreading, interviewer asked me to write a program, to write the contents of three files(F1,F2,F3) in to a new File F4, using multithreading , first thread should read the first file and second thread should read second file, so the File F4 should contain F1's contents in first then F2's contents after that etc. I tried to give my best shot, but i couldn't get a way to ensure that the first thread is reading the first file and write to F4 then second thread reading the second file and writing once first file is written completely into F4 and so on ..how to do this?
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Jan 10, 2014
What i basically do is that i read the information of what course that needs to be updated with a new course date and then i log into the wordpress page and navigate to the course and add the date.
I need the java program to be able to do these following actions.
1. Open a webpage
2. write to a form
3. click a button
4. search for a text on screen
5. click on a specific place on the screen/click on a link
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and so on...
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How to create background threads from my model that will read from and write to a GUI using Tasks and/or Services.
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Write a program that reads an integer and displays, using asterisks, a filled diamond of the given side length. For example, if the side length is 4 the program should display.
*
***
*****
*******
*****
***
*
I have it where it displays the top half of the diamond. But i cannot figure out how to get it to draw the bottom half.
import java.util.*;
public class E616 {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
System.out.print("Enter number of rows. ");
int N=input.nextInt();
[code]...
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May 29, 2014
I designed a Java desktop application (i.e the app runs on local computer), everything is fine until when I compiled the program and wanted to run it on another computer then it tell me "java.sql.SQLException: attempt to write to only read database".
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Apr 21, 2015
I have a requirement to read all the xml files from a parent folder and write in a spreadsheet(separate spreadsheet for each xml file)
I have written the below code in which xml and excel file name are hardcoded. The format of xml file is same.
package xmlexcel;
import org.apache.poi.hssf.usermodel.*;
import java.util.ArrayList;
import java.awt.List;
import java.io.*;
import java.util.ArrayList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.SAXException;
[Code]...
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Mar 6, 2014
i have to write more than 100000 rows in a excel sheet (file size more than 20 MB) via java.
when i use XSSF, i am getting below Error.
java.lang.OutOfMemoryError: Java heap space
at org.apache.xmlbeans.impl.store.Saver$TextSaver.resize(Saver.java:1592)
at org.apache.xmlbeans.impl.store.Saver$TextSaver.preEmit(Saver.java:1223)
at org.apache.xmlbeans.impl.store.Saver$TextSaver.emit(Saver.java:1144)
[Code]....
when i use HSSF , i am getting the below Error.
java.lang.OutOfMemoryError: Java heap space
I have tried increasing the java heap size , by giving upto -Xms1500m -Xmx2048m
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