Develop Reference

Weka runtime error

I am trying to copy the first attribute of my training dataset, and copy the corresponding from Test set for book-keeping purpose. My code compiles successfully. But I am not able to run it.
I get the following errorwhen run java WekaRF
Exception in thread "main" java.lang.NoClassDefFoundError: weka/core/converters/CSVLoader
at WekaRF.main(WekaRF.java:17)
Caused by: java.lang.ClassNotFoundException: weka.core.converters.CSVLoader
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more
If I run, java -cp weka-3-8-1/weka.jar WekaRF, I get
Error: Could not find or load main class WekaRF
My code is given below
import java.io.*;
import java.util.Random;
import weka.classifiers.Evaluation;
import weka.classifiers.trees.RandomForest;
import weka.core.Instances;
import weka.filters.unsupervised.attribute.Remove;
import weka.core.converters.*;
public class WekaRF {
public static void main(String[] args) {
int percent = 60;
Instances data = null;
try {
CSVLoader loader = new CSVLoader();
loader.setSource(new File("../../rf.csv"));
data = loader.getDataSet();
} catch (Exception e) {
e.printStackTrace();
return;
}
int TrainSize = (int) Math.round(data.numInstances() * percent/ 100);
int TestSize = data.numInstances() - TrainSize;
Instances Train = new Instances(data, 0, TrainSize);
Instances Test = new Instances(data, TrainSize, TestSize);
System.out.println(Test.attribute(0).name());
Remove remove = new Remove();
String[] options = new String[2];
options[0] = "-R";
options[1] = "1";
remove.setOptions(options);
remove.setInputFormat(data2);
Test = Filter.useFilter(Test, remove);
Train.setClassIndex(Train.numAttributes() - 1);
}
}

Your classpath does not include current directory so java didn't see your WekaRF class.
Try to use java -cp .;weka-3-8-1/weka.jar WekaRF instead.
Notice dot at the start of -cp argument. It denotes current directory.
Upd: Character used to separate individual class path entries is operation system-depended. Windows uses ; and most other systems use :. The actual path separator can be retrieved by querying java.io.File::pathSeparator field.

In Java, on Windows how do i determine if drive is local or remote drive

This is required for Windows machines only to decide whether to enforce Windows Explorer 259 path char limit. I have the following method that uses Filestore determine if partition is a windows based partition but I also need to know if local or remote drive.
Im using Java 8.
Update
I tried against root of networked drive mounted on Z:\, this actually throws an exception so that does help deterine if networked or not, but I cant see how to know that Z:\Drive is mounting \nas because if I want to find fs I need to use \nas ?
public static boolean isNTFSOrFAT32(String newPath)
{
Path root = Paths.get(newPath).getRoot();
if(root==null)
{
return false;
}
try
{
FileStore fs = Files.getFileStore(root);
if (fs.type().equals("NTFS")
|| fs.type().equals("FAT")
|| fs.type().equals("FAT32))
{
return true;
}
return false;
}
catch(IOException ex)
{
MainWindow.logger.log(Level.SEVERE, ex.getMessage(), ex);
return false;
}
}
I would prefer a proper pure Java implementation, the answer given as a possible duplicate Java: how to determine the type of drive a file is located on? is rather flaky code
Update
package com.test;
import java.nio.file.FileStore;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Iterator;
public class Fs
{
public static void main(String[] args) throws Exception
{
Path p = Paths.get("Z:\\\\").getRoot();
System.out.println(p+":"+Files.exists(p));
Iterator<FileStore> i = p.getFileSystem().getFileStores().iterator();
while(i.hasNext())
{
FileStore fs = i.next();
System.out.println("--" + fs.type() + ":" + fs.name() + ":" + fs.getTotalSpace());
}
//Files.getFileStore(p);
Path p2 = Paths.get("\\nas").getRoot();
System.out.println(p2+":"+Files.exists(p2));
FileStore fs2 = Files.getFileStore(p2);
System.out.println("--" + fs2.type() + ":" + fs2.name() + ":" + fs2.getTotalSpace());
FileStore fs = Files.getFileStore(p);
}
}
Outputs
Z:\:false
--NTFS::478854123520
--NTFS:New Volume:1000202039296
--exFAT:MacMusic:2000378920960
\:true
--NTFS::478854123520
Exception in thread "main" java.nio.file.NoSuchFileException: Z:\
at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:79)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
at sun.nio.fs.WindowsLinkSupport.getFinalPath(WindowsLinkSupport.java:107)
at sun.nio.fs.WindowsFileStore.create(WindowsFileStore.java:83)
at sun.nio.fs.WindowsFileSystemProvider.getFileStore(WindowsFileSystemProvider.java:482)
at java.nio.file.Files.getFileStore(Files.java:1461)
at com.jthink.songkong.Fs.main(Fs.java:26)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

Program dismisses steps when running quickly (Java)

I am running a tool that runs an external Java program several times in its operation. The external tool starts with opening a JOptionPane inside a JFrame.
Here is a test script I wrote to try to solve my issue.
import java.io.File;
public class Test {
public static void main(String[] args) throws Exception {
for(int i=0; i<6; i++) {
//Thread.sleep(1000);
String toRun = "java -jar \"" + "C:\\Folder\\File.jar" + "\" " + i;
Runtime.getRuntime().exec(toRun, null, new File("C:\\Folder"));
}
}
}
When this runs, only the final run's JOptionPane (i=5) appears, but it seems that others are "trying" to appear as panes seem to be opening and immediately closing.
When I uncomment the Thread.sleep however, all of the panes open separately. If i set the sleep to 300 (0.3 seconds) about half of the panes appear, usually the first and last ones.
I would like to find a way to run all instances of the external program fully without needing to use Thread.sleep() at all, if possible.
Edit: As per requirement's I've minimalised my external program as well.
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class File {
static JFrame frame = new JFrame("Frame");
private static String doc1Address = "C:\\Folder\\doc1.csv";
private static String doc2Address = "C:\\Folder\\doc2.csv";
public static void main(String[] args) throws Exception {
if(args.length == 1) {
SimpleDateFormat form = new SimpleDateFormat("yyyy-MM-dd hh-mm-ss");
Date date = new Date();
String currentDate = form.format(date);
//Save Backup of doc1
String doc1BackAddress = doc1Log.substring(0, doc1Log.length()-15) + "doc1Back " + currentDate + ".csv";
Path todoc1 = Paths.get(doc1Address);
Path todoc1Back = Paths.get(doc1BackAddress);
Files.copy(todoc1, todoc1Back);
Files.setAttribute(todoc1Back, "dos:readonly", true);
//Save Backup of doc2
String doc2BackAddress = doc2Log.substring(0, doc2Log.length()-16) + "doc2Back " + currentDate + ".csv";
Path todoc2 = Paths.get(doc2Address);
Path todoc2Back = Paths.get(doc2BackAddress);
Files.copy(todoc2, todoc2Back);
Files.setAttribute(todoc2Back, "dos:readonly", true);
//Format JFrame
frame.pack();
frame.setLodoc1ionRelativeTo(null);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JOptionPane.showMessageDialog(frame, args[0]);
frame.dispose();
}
}
}

Found my own issue; since the backup files use the format yyyy-MM-dd hh-mm-ss, and files saved during the same second result in a FileAlreadyExists Exception, meaning only the first file to finish saving allows the program to continue running.
Having a 1 second pause results in the files having different save names, so no error occurs.
Having a sub-1 second pause results in some file name overlap, but some different names too, hence some files appear.
Solution: either change the name format (i.e. include milliseconds), or include the backup functions in an if-statement, that is ignored if the file with the same time already exists.
(also; thank you #ErwinBolwidt, in being encouraged to format my question properly I realised that the issue in my code was not where I assumed it to be).

Problems reading an ini file in Java

I am having trouble using Apache commons configuration to read an ini file. I attached the imports incase I am missing something. Below is an example I found on stackoverflow, and as far as I can find, there are no other examples to look at. The problem is iniObj. Using Eclipse it is highlighted in red.
If I initialize the variable, new "HierarchicalINIConfiguration(iniFile); gets angry and wants to add a try/catch or throws... which should be no problem... but then the try/catch or throws gets angry and says "No exception of type ConfigurationException can be thrown; an exception type must be a subclass of Throwable."
Which then brought me to this question. I added the commons lang 3.1. I have commons config 1.9, commons collections 3.2.1. commons logging 1.1.1 as well. I have also tried this with commons config 1.8 and lang 2.6. Now I get a new error "Exception in thread "main" java.lang.NullPointerException at com.toolbox.dev.ReadIni.main(ReadIni.java:28)" You can see the new code below after the adjustments I made to try and resolve the errors.
My code:
import java.util.Iterator;
import java.util.Set;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.HierarchicalINIConfiguration;
import org.apache.commons.configuration.SubnodeConfiguration;
public static void main(String[] args) throws ConfigurationException {
String iniFile = "file.ini";
HierarchicalINIConfiguration iniConfObj = new HierarchicalINIConfiguration(iniFile);
// Get Section names in ini file
Set setOfSections = iniConfObj.getSections();
Iterator sectionNames = setOfSections.iterator();
while(sectionNames.hasNext()) {
String sectionName = sectionNames.next().toString();
HierarchicalINIConfiguration iniObj = null;
SubnodeConfiguration sObj = iniObj.getSection(sectionName);
Iterator it1 = sObj.getKeys();
while (it1.hasNext()) {
// Get element
Object key = it1.next();
System.out.print("Key " + key.toString() + " Value " +
sObj.getString(key.toString()) + "\n");
}
}
}
Original code from Stack Overflow:
import java.util.Iterator;
import java.util.Set;
import org.apache.commons.configuration.HierarchicalINIConfiguration;
import org.apache.commons.configuration.SubnodeConfiguration;
public class ReadIni {
public static void main(String[] args) {
String iniFile = "";
HierarchicalINIConfiguration iniConfObj = new HierarchicalINIConfiguration(iniFile);
// Get Section names in ini file
Set setOfSections = iniConfObj.getSections();
Iterator sectionNames = setOfSections.iterator();
while(sectionNames.hasNext()) {
String sectionName = sectionNames.next().toString();
SubnodeConfiguration sObj = iniObj.getSection(sectionName);
Iterator it1 = sObj.getKeys();
while (it1.hasNext()) {
// Get element
Object key = it1.next();
System.out.print("Key " + key.toString() + " Value " +
sObj.getString(key.toString()) + "\n");
}
}

Since you have already initialized the HierarchicalINIConfiguration (second line in "main") as :
HierarchicalINIConfiguration iniConfObj = new HierarchicalINIConfiguration(iniFile);
I believe you want to remove HierarchicalINIConfiguration iniObj = null; (around 5 lines down) from your code and change
SubnodeConfiguration sObj = iniObj.getSection(sectionName);
to (use iniConfObj in place of iniObj)
SubnodeConfiguration sObj = iniConfObj.getSection(sectionName);

This doesn't look promising ?
HierarchicalINIConfiguration iniObj = null;
SubnodeConfiguration sObj = iniObj.getSection(sectionName);
Is this line 28 ?

You could try JINIFile. Is a translation of the TIniFile from Delphi, but for java. It fully supports all the INI file features
https://github.com/SubZane/JIniFile

Indentation issues with Staxmate API

I am using Staxmate API to generate XML file. After reading the tutorial: http://staxmate.codehaus.org/Tutorial I tried making the changes in my code. At last I added the call
doc.setIndentation("\n ", 1, 1);
Which causes the newly generated XML file to be empty! Without this method call entire XML file gets generated as expected.
Suspecting something fishy in in project setup, I created a Test class in the same package with the code given in tutorial:
package ch.synlogic.iaf.export;
import java.io.File;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import org.codehaus.staxmate.SMOutputFactory;
import org.codehaus.staxmate.out.SMOutputDocument;
import org.codehaus.staxmate.out.SMOutputElement;
public class Test {
public static void main(String[] args) {
main("c:\\tmp\\empl.xml");
}
public static void main(String fname)
{
// 1: need output factory
SMOutputFactory outf = new SMOutputFactory(XMLOutputFactory.newInstance());
SMOutputDocument doc;
try {
doc = outf.createOutputDocument(new File(fname));
// (optional) 3: enable indentation (note spaces after backslash!)
doc.setIndentation("\n ", 1, 1);
// 4. comment regarding generation time
doc.addComment(" generated: "+new java.util.Date().toString());
SMOutputElement empl = doc.addElement("employee");
empl.addAttribute(/*namespace*/ null, "id", 123);
SMOutputElement name = empl.addElement("name");
name.addElement("first").addCharacters("Tatu");
name.addElement("last").addCharacters("Saloranta");
// 10. close the document to close elements, flush output
doc.closeRoot();
} catch (XMLStreamException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Now when I invoke the main(String) method from my code the problem still persists whereas if I just run class Test as it is it works smoothly! My code involves database initializations and some other product specific actions.
I am lost, any thoughts on how should I proceed with this?

Indentation works with Woodstox API
WstxOutputFactory factory = new WstxOutputFactory();
factory.setProperty(WstxOutputFactory.P_AUTOMATIC_EMPTY_ELEMENTS, true);
SMOutputFactory outf = new SMOutputFactory(factory);
doc = outf.createOutputDocument(fout);
doc.setIndentation("\n ", 1, 1);

Below works for me -
context.setIndentation("\r\n\t\t\t\t\t\t\t\t", 2, 1); // indent by windows lf and 1 tab per level