i am having a trouble adding a string into an ArrayList. my goal is to create a list of an array using a for loop. however each time it is looping it seem always erase the previous data and then it replace it with the new data, so the ArrayList only have the value of 1 instead of 4. here is the full code
public class SerialDemo {
private static File f;
private static Save obj1;
private static Save obj;
private static int number = 4;
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
//getData("newFile.txt");
for(int i = 0; i < number;i++) {
obj = new Save();
obj.arrayLocationX.add(String.valueOf(10 * i));
obj.arrayLocationY.add(String.valueOf(20 * i));
obj.arrayTitle.add(String.valueOf(30 * i));
obj.arrayDescription.add(String.valueOf(40 * i));
obj.arrayNumber.add(""+i);
}
for(String x:obj.arrayLocationX) {
System.out.println(obj.arrayLocationX);
}
//setData("newFile.txt");
/*getData("newFile.txt");
for(int i = 0; i < obj.arrayLocationX.size(); i++) {
System.out.println("Value of Desc"+obj1.arrayNumber);
System.out.println("Value of locX"+obj1.arrayLocationX.get(i));
System.out.println("Value of locY"+obj1.arrayLocationY.get(i));
System.out.println("Value of Tit"+obj1.arrayTitle.get(i));
System.out.println("Value of Desc"+obj1.arrayDescription.get(i));
System.out.println(" ");
System.out.println(obj.arrayDescription.size());
}*/
}catch(Exception e) {
}
}
private static void setData(String fileName) {
// set the object or data
try {
f = new File(fileName);
FileOutputStream fps;
fps = new FileOutputStream(f);
ObjectOutputStream dos = new ObjectOutputStream(fps);
dos.writeObject(obj);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch(IOException e) {
}
}
private static void getData(String fileName) {
// get the object or data
try {
f = new File(fileName);
FileInputStream fin = new FileInputStream(f);
ObjectInputStream Oin = new ObjectInputStream(fin);
obj1 = (Save) Oin.readObject();
}catch(FileNotFoundException e) {
}catch(IOException e) {
}catch(ClassNotFoundException e) {
}
}
}
class Save implements Serializable {
ArrayList<String> arrayNumber = new ArrayList<String>();
ArrayList<String> arrayLocationX = new ArrayList<String>();
ArrayList<String> arrayLocationY = new ArrayList<String>();
ArrayList<String> arrayTitle = new ArrayList<String>();
ArrayList<String> arrayDescription = new ArrayList<String>();
}
A new obj is created in every iteration hence your added string is lost. Try moving obj = new Save(); before the loop.
for(int i = 0; i < number;i++) {
obj = new Save();
obj is instantiated as a new Save every time the loop begins again. This means all your progress from the previous loop is lost and the new Save is the one that receives the inserts. You only want to create obj once, somewhere before the loop. Swapping the order of the lines should cause the program to work.
obj = new Save();
for(int i = 0; i < number;i++) {
Related
I was given an assignment to write all ordered contents of given files into a result.txt. At first, the filenames are split into different Arraylists where each file contains a label in a format #n/N where N is the total number of files. e.g.
British explorer James Clark Ross led the first
expedition to reach the north magnetic pole
#001/004
from a file 1831-06-01.txt
The problem with my code is that it has written in order 1,4,2,3 respectively. However, the result must be in order 1,2,3,4. This may be due to a lack of synchronization. Nonetheless, I am still struggling to fix the problem.
This is my code:
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.*;
class PopThread implements Runnable {
ArrayList<String> fileList;
public PopThread(ArrayList<String> fileList) {
this.fileList = fileList;
}
#Override
public void run() {
//System.out.println("running\n");
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
long startTime = System.nanoTime();
System.out.println("fileList: " + fileList);
ArrayList<String> sortedFileList = sortFiles(fileList);
File resultFile = new File("result.txt");
for (String filename : sortedFileList) {
Writer w1 = new Writer(filename, resultFile);
Thread t = new Thread(w1);
t.setPriority(Thread.MAX_PRIORITY);
t.start();
}
long stopTime = System.nanoTime();
//System.out.println("Total execution time: " + (stopTime - startTime));
}
public ArrayList<String> readFiles(String filename) {
ArrayList<String> list = new ArrayList<String>();
try {
File myObj = new File(filename);
Scanner s = new Scanner(myObj);
while (s.hasNext()) {
list.add(s.next());
}
s.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return list;
}
public int getNumber(String filename) {
String lastLine = "";
String sCurrentLine;
int identifier_integer = -1;
try {
BufferedReader br = new BufferedReader(new FileReader(filename));
while ((sCurrentLine = br.readLine()) != null) {
lastLine = sCurrentLine;
}
String identifier_number = lastLine.substring(1,4);
identifier_integer = Integer.parseInt(identifier_number);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
return identifier_integer;
}
public ArrayList<String> sortFiles(ArrayList<String> listFileName) {
int i = listFileName.size();
boolean sorted = false;
while ( (i > 1) && (!(sorted)) ) {
sorted = true;
for (int j = 1; j < i; j++) {
if ( getNumber(listFileName.get(j-1)) > getNumber(listFileName.get(j)) ) {
String temp = listFileName.get(j-1);
listFileName.set(j-1, listFileName.get(j));
listFileName.set(j, temp);
sorted = false;
}
}
i--;
}
return listFileName;
}
}
class Writer implements Runnable {
String filename;
File resultFile;
public Writer(String filename, File resultFile) {
this.filename = filename;
this.resultFile = resultFile;
}
#Override
public void run() {
String content;
content = readFromFile(filename);
writeToFile(resultFile, content);
}
private static void writeToFile(File resultFile, String content) {
try {
BufferedWriter writer = new BufferedWriter(new FileWriter(resultFile, true));
writer.write(content);
//writer.write("file content written");
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
static String readFromFile(String filename) {
StringBuffer content = new StringBuffer();
try {
String text;
BufferedReader reader = new BufferedReader(new FileReader(filename));
while ((text = reader.readLine()) != null) {
content.append(text);
content.append("\n");
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
return content.toString();
}
}
public class q4 {
public static void main(String[] args) {
ArrayList<String> filesOne = new ArrayList<String>();
filesOne.add("1831-06-01.txt");
filesOne.add("2003-08-27.txt");
ArrayList<String> filesTwo = new ArrayList<String>();
filesTwo.add("1961-04-12.txt");
filesTwo.add("1972-12-11.txt");
PopThread popRunnableOne = new PopThread(filesOne);
PopThread popRunnableTwo = new PopThread(filesTwo);
Thread threadOne = new Thread(popRunnableOne);
Thread threadTwo = new Thread(popRunnableTwo);
threadOne.start();
threadTwo.start();
try {
threadOne.join();
threadTwo.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
( NOTE: The class q4 cannot be altered)
This assignment is horrible. You have my sympathy.
Your two threads will have to communicate with each other. Each thread will have to know, what is the filename that the other thread wants to output next. And, they will have to take turns. Each thread needs to loop:
While the date on my next file is less than or equal to the date on the other thread's next file, output my next file,
Tell the other thread, "it's your turn,"
If I have no more files, then exit (return from the run() method), otherwise, wait for the other thread to tell me it's my turn again,
Go back to step 1.
Having to take turns is the worst part of the assignment. Any time you find yourself needing to make threads take turns doing something—any time you need to make threads do things in a particular order—that's a clear sign that all of the things should be done by a single thread.
The only way threads can communicate is through shared variables. Your instructor has done you a huge disservice by telling you not to modify the q4 class. That prevents you from passing any shared objects in to your PopThread implementation through its constructor.
The only other way your two threads can share any variables is by making the variables static. Forcing you to use static is the second worst part of the assignment. If you go on to study software engineering, you will learn that static is an anti-pattern. Programs that use static variables are brittle (i.e., hard to modify), and they are hard to test.
Forcing you to use static variables also will make your threads do extra work to figure out who is who. Normally, I would do something like this so that each thread would automatically know which state is its own, and which belongs to the other guy:
class SharedState { ... }
class PopThread {
public PopThread(
SharedState myState,
SharedState otherThreadState,
ArrayList<String> fileList
) {
this.myState = myState;
this.otherGuyState = otherThreadState;
this.fileList = fileList;
...initialize this.myState...
}
...
}
class q4 {
public static void main(String[] args) {
SharedState stateOne = new SharedState();
SharedState stateTwo = new SharedState();
PopThread popRunnableOne = new PopThread(stateOne, stateTwo, filesOne);
PopThread popRunnableTwo = new PopThread(stateTwo, stateOne, filesTwo);
...
}
}
The best way I can think of with static variables would be to have an array of two SharedState, and have the threads use an AtomicInteger to each assign themself one of the two array slots:
class PopThread {
static SharedState[] state = new SharedState [2];
static AtomicInteger nextStateIndex = new AtomicInteger(0);
public PopThread(
SharedState myState,
SharedState otherThreadState,
ArrayList<String> fileList
) {
myStateIndex = nextStateIndex.getAndIncrement();
otherGuysStateIndex = myStateIndex ^ 1;
this.fileList = fileList;
...initialize state[myStateIndex]...
}
...
}
I want to return an array that is accessible by other objects after having read a text file. My instruction parsing class is:
import java.io.*;
public class Instruction {
public String[] instructionList;
public String[] readFile() throws IOException {
FileInputStream in = new FileInputStream("directions.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(in));
int n = 5;
instructionList = new String[n];
for (int j = 0; j < instructionList.length; j++) {
instructionList[j] = br.readLine();
}
in.close();
return instructionList;
}
}
The above takes in a text file with 5 lines of text in it. In my main() I want to run that function and have the string array be accessible to other objects.
import java.util.Arrays;
public class RoverCommand {
public static void main(String[] args) throws Exception {
Instruction directions = new Instruction();
directions.readFile();
String[] directionsArray;
directionsArray = directions.returnsInstructionList();
System.out.println(Arrays.toString(directionsArray));
}
}
What's the best way to do that? I would need the elements of the array to be integers if they are numbers and strings if they are letters. P.S. I'm brand new to Java. is there a better way to do what I'm doing?
You don't have to use generics. I try to catch exceptions in the accessors and return null if anything blows up. So you can test if the value returned is null before proceeding.
// Client.java
import java.io.IOException;
public class Client {
public static void main(String args[]) {
try {
InstructionList il = new InstructionList();
il.readFile("C:\\testing\\ints.txt", 5);
int[] integers = il.getInstructionsAsIntegers();
if (integers != null) {
for (int i : integers) {
System.out.println(i);
}
}
} catch (IOException e) {
// handle
}
}
}
// InstructionList.java
import java.io.*;
public class InstructionList {
private String[] instructions;
public void readFile(String path, int lineLimit) throws IOException {
FileInputStream in = new FileInputStream(path);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
instructions = new String[lineLimit];
for (int i = 0; i < lineLimit; i++) {
instructions[i] = br.readLine();
}
in.close();
}
public String[] getInstructionsAsStrings() {
return instructions; // will return null if uninitialized
}
public int[] getInstructionsAsIntegers() {
if (this.instructions == null) {
return null;
}
int[] instructions = new int[this.instructions.length];
try {
for (int i = 0; i < instructions.length; i++) {
instructions[i] = new Integer(this.instructions[i]);
}
} catch (NumberFormatException e) {
return null; // data integrity fail, return null
}
return instructions;
}
}
check instructionList is null or not. if it is null, call readFile method.
public String[] returnsInstructionList() {
if (instructionList== null){
try { readFile(); } catch(Exception e){}
}
return instructionList;
}
because of readFile can throw exception, it would be good to use one extra variable. like:
private boolean fileReaded = false;
public String[] returnsInstructionList() {
if (!fileReaded){
fileReaded = true;
try { readFile(); } catch(Exception e){}
}
return instructionList;
}
and if readFile can be run concurrently, easiest way to make function synchronized, like
private boolean fileReaded = false;
public synchronized void readFile() throws IOException {
.
.
.
}
public synchronized String[] returnsInstructionList() {
if (!fileReaded){
fileReaded = true;
try { readFile(); } catch(Exception e){}
}
return instructionList;
}
There is no guarantee that readFile is called before returnsInstructionList is invoked. Leaving you returnsInstructionList returning null.
I would :
public String[] getContentsFromFile(String fileName) throws IOException {
FileInputStream in = new FileInputStream(fileName);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
int n = 5;
instructionList = new String[n];
for (int j = 0; j < instructionList.length; j++) {
instructionList[j] = br.readLine();
}
in.close();
return instructionList;
}
Part two to the question you can use generics. To achieve what you want but you have to incorporate a way to say what it is.
Eg
public class Foo {
public ReturnForFoo returnAStringOrIntger(boolean val) {
if(val){
return new ReturnForFoo("String", ValueType.STRING) ;
}
return new ReturnForFoo(10, ValueType.INTEGER); //int
}
}
public class ReturnForFoo {
Object value;
ValueType type;
public ReturnForFoo(Object value, ValueType type) {
this.value=value;
this.type=type
}
// Asume you have getters for both value and value type
public static ENUM ValueType {
STRING,
INTEGER,
UNKNOWN
}
}
This code is in your main.
Foo foo = new Foo();
String value;
int val;
ReturnForFoo returnForFoo = foo.returnAStringOrIntger(true);
// NOTE you can use switch instead of if's and else if's. It will be better
if(returnForFoo.getValueType().equals(ValueType.INTEGER)){
val = (int) returnForFoo.getValue();
} else if(returnForFoo.getValueType().equals(ValueType.STRING)){
value = (String) returnForFoo.getValue();
} else {
// UNKOWN Case
}
Well what i am trying to achieve is to save pairs of words in a sentence and if the word is already there , i am trying to save a list of words against one.
To save the pairing as there could many millions as my data set file is very large , i opted for orientdb. I dont know if i am approaching it correctly but orientdb is very slow. After 8 hours of running it has only made pairs for 12000 sentences.
As far as i have checked the major slowdown was in browsing cluster.
Attached is my code, please if ant one can give any pointers over my approach.
public static void main(String[] args) {
// TODO Auto-generated method stub
Main m = new Main();
m.openDatabase();
m.readFile("train_v2.txt");
m.closeDatabase();
}
}
class Main {
ODatabaseDocumentTx db;
Map<String, Object> index;
List<Object> list = null;
String pairing[];
ODocument doc;
Main() {
}
public void closeDatabase() {
if (!db.isClosed()) {
db.close();
}
}
void openDatabase() {
db = new ODatabaseDocumentTx("local:/databases/model").open("admin",
"admin");
doc = new ODocument("final");
}
public void readFile(String filename) {
InputStream ins = null; // raw byte-stream
Reader r = null; // cooked reader
int i = 1;
BufferedReader br = null; // buffered for readLine()
try {
String s;
ins = new FileInputStream(filename);
r = new InputStreamReader(ins, "UTF-8"); // leave charset out
// for
// default
br = new BufferedReader(r);
while ((s = br.readLine()) != null) {
System.out.println("" + i);
createTermPair(s.replaceAll("[^\\w ]", "").trim());
i++;
}
} catch (Exception e) {
System.err.println(e.getMessage()); // handle exception
} finally {
closeDatabase();
if (br != null) {
try {
br.close();
} catch (Throwable t) { /* ensure close happens */
}
}
if (r != null) {
try {
r.close();
} catch (Throwable t) { /* ensure close happens */
}
}
if (ins != null) {
try {
ins.close();
} catch (Throwable t) { /* ensure close happens */
}
}
}
}
private void createTermPair(String phrase) {
phrase = phrase + " .";
String[] word = phrase.split(" ");
for (int i = 0; i < word.length - 1; i++) {
if (!word[i].trim().equalsIgnoreCase("")
&& !word[i + 1].trim().equalsIgnoreCase("")) {
String wordFirst = word[i].toLowerCase().trim();
String wordSecond = word[i + 1].toLowerCase().trim();
String pair = wordFirst + " " + wordSecond;
checkForPairAndWrite(pair);
}
}
}
private void checkForPairAndWrite(String pair) {
try {
pairing = pair.trim().split(" ");
if (!pairing[1].equalsIgnoreCase(" ")) {
index = new HashMap<String, Object>();
for (ODocument docr : db.browseCluster("final")) {
list = docr.field(pairing[0]);
}
if (list == null) {
list = new ArrayList<>();
}
list.add("" + pairing[1]);
if (list.size() >= 1)
index.put(pairing[0], list);
doc.fields(index);
doc.save();
}// for (int i = 0; i < list.size(); i++) {
// System.out.println("" + list.get(i));
// }
} catch (Exception e) {
}
return;
}
}
I'm trying to create XML report, that can be opened as xls table.
I have following output:
<Report>
<test>
<string>4.419</string>
<string>4.256</string>
</test>
</Report>
from this code:
/**
* declare arrays
*/
// ArrayList<String> test = new ArrayList<String>();
ArrayList<String> stats = new ArrayList<String>();
// ArrayList<String> count = new ArrayList<String>();
/**
*return array list with loading times
*/
public ArrayList launch() {
for (int i = 0; i < 2; i++) {
// ui.off();
// ui.on();
device.pressHome();
ui.openProgramInMenu("ON");
long TStart = System.currentTimeMillis();
ui.detectContactList();
long TStop = System.currentTimeMillis();
float res = TStop - TStart;
res /= 1000;
ui.log("[loading time]: " + res);
// ui.off();
test.add(i, "Loading time");
stats.add(i, Float.toString(res));
count.add(i, Integer.toString(i));
}
System.out.println(stats);
}
where rep.class has code:
public class ReportSettings {
public List<String> test = new ArrayList<String>();
public List<String> count = new ArrayList<String>();
public List<String> stats = new ArrayList<String>();
/**
* Test method
*/
public static void main(String[] args) {
ReportSettings rep = new ReportSettings();
rep.saveXML("report/data.xml");
// System.out.println(rep.test);
// rep = rep.loadXML("report/data.xml");
// System.out.println(rep.home);
System.out.println(rep.getXML());
}
public void createReport() {
ReportSettings rep = new ReportSettings();
rep.saveXML("report/data.xml");
}
public String getXML() {
XStream xstream = new XStream();
xstream.alias("Report", ReportSettings.class);
xstream.autodetectAnnotations(true);
return xstream.toXML(this);
}
public void saveXML(String filename) {
if (!filename.contains(".xml")) {
System.out.println("Error in saveReport syntax");
return;
}
String xml = this.getXML();
File f = new File(filename);
try {
FileOutputStream fo = new FileOutputStream(f);
fo.write(xml.getBytes());
fo.close();
}
catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
}
public ReportSettings loadXML(String filename) {
if (!filename.endsWith(".xml")) {
System.out.println("Error in loadReport syntax!");
throw new RuntimeException("Error in loadReport syntax!");
}
File f = new File(filename);
XStream xstream = new XStream(new DomDriver());
xstream.alias("Report", ReportSettings.class);
xstream.autodetectAnnotations(true);
ReportSettings ort = (ReportSettings)xstream.fromXML(f);
return ort;
}
}
Finally I want to create table from 3 ArrayList, where {stats, count, test}*i. /n
How can I use Xstream.alias to change <strings> to <somethingAnother> in the XML file? I need to change them to stringOne and stringTwo as example.
You can use the ClassAliasMapper in Xstream to give the items in your collection a different tag when serializing to XML.
You add a block like this (for each collection: stats, count, test):
ClassAliasingMapper statsMapper = new ClassAliasingMapper(xstream.getMapper());
mapper.addClassAlias("somethingAnother", String.class);
xstream.registerLocalConverter(
InteractionSession.class,
"stats",
new CollectionConverter(mapper)
);
Hello I have a problem wherein I have to read a huge csv file. remove first field from it, then store only unique values to a file. I have written a program using threads which implements producer-consumer pattern.
Class CSVLineStripper does what the name suggests. Takes a line out of csv, removes first field from every line and adds it to a queue. CSVLineProcessor then takes that field stores all one by one in an arraylist and checks if fields are unique so only uniques are stored. Arraylist is only used for reference. every unique field is written to a file.
Now what is happening is that all fields are stripped correctly. I run about 3000 lines it's all correct. When I start the program for all lines, which are around 7,00,000 + lines, i get incomplete records, about 1000 unique are not taken. Every field is enclosed in double-quotes. What is weird is that the last field in the file that is generated is an incomplete word and ending double quote is missing. Why is this happening?
import java.util.*;
import java.io.*;
class CSVData
{
Queue <String> refererHosts = new LinkedList <String> ();
Queue <String> uniqueReferers = new LinkedList <String> (); // final writable queue of unique referers
private int finished = 0;
private int safety = 100;
private String line = "";
public CSVData(){}
public synchronized String getCSVLine() throws InterruptedException{
int i = 0;
while(refererHosts.isEmpty()){
if(i < safety){
wait(10);
}else{
return null;
}
i++;
}
finished = 0;
line = refererHosts.poll();
return line;
}
public synchronized void putCSVLine(String CSVLine){
if(finished == 0){
refererHosts.add(CSVLine);
this.notifyAll();
}
}
}
class CSVLineStripper implements Runnable //Producer
{
private CSVData cd;
private BufferedReader csv;
public CSVLineStripper(CSVData cd, BufferedReader csv){ // CONSTRUCTOR
this.cd = cd;
this.csv = csv;
}
public void run() {
System.out.println("Producer running");
String line = "";
String referer = "";
String [] CSVLineFields;
int limit = 700000;
int lineCount = 1;
try {
while((line = csv.readLine()) != null){
CSVLineFields = line.split(",");
referer = CSVLineFields[0];
cd.putCSVLine(referer);
lineCount++;
if(lineCount >= limit){
break;
}
}
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("<<<<<< PRODUCER FINISHED >>>>>>>");
}
private String printString(String [] str){
String string = "";
for(String s: str){
string = string + " "+s;
}
return string;
}
}
class CSVLineProcessor implements Runnable
{
private CSVData cd;
private FileWriter fw = null;
private BufferedWriter bw = null;
public CSVLineProcessor(CSVData cd, BufferedReader bufferedReader){ // CONSTRUCTOR
this.cd = cd;
try {
this.fw = new FileWriter("unique_referer_dump.txt");
} catch (IOException e) {
e.printStackTrace();
}
this.bw = new BufferedWriter(fw);
}
public void run() {
System.out.println("Consumer Started");
String CSVLine = "";
int safety = 10000;
ArrayList <String> list = new ArrayList <String> ();
while(CSVLine != null || safety <= 10000){
try {
CSVLine = cd.getCSVLine();
if(!list.contains(CSVLine)){
list.add(CSVLine);
this.CSVDataWriter(CSVLine);
}
} catch (Exception e) {
e.printStackTrace();
}
if(CSVLine == null){
break;
}else{
safety++;
}
}
System.out.println("<<<<<< CONSUMER FINISHED >>>>>>>");
System.out.println("Unique referers found in 30000 records "+list.size());
}
private void CSVDataWriter(String referer){
try {
bw.write(referer+"\n");
} catch (Exception e) {
e.printStackTrace();
}
}
}
public class RefererCheck2
{
public static void main(String [] args) throws InterruptedException
{
String pathToCSV = "/home/shantanu/DEV_DOCS/Contextual_Work/excite_domain_kw_site_wise_click_rev2.csv";
CSVResourceHandler csvResHandler = new CSVResourceHandler(pathToCSV);
CSVData cd = new CSVData();
CSVLineProcessor consumer = new CSVLineProcessor(cd, csvResHandler.getCSVFileHandler());
CSVLineStripper producer = new CSVLineStripper(cd, csvResHandler.getCSVFileHandler());
Thread consumerThread = new Thread(consumer);
Thread producerThread = new Thread(producer);
producerThread.start();
consumerThread.start();
}
}
This is how a sample input is:
"xyz.abc.com","4432"."clothing and gifts","true"
"pqr.stu.com","9537"."science and culture","false"
"0.stu.com","542331"."education, studies","false"
"m.dash.com","677665"."technology, gadgets","false"
Producer stores in queue:
"xyz.abc.com"
"pqr.stu.com"
"0.stu.com"
"m.dash.com"
Consumer stores uniques in the file, but after opening file contents one would see
"xyz.abc.com"
"pqr.stu.com"
"0.st
Couple things, you are breaking after 700k, not 7m, also you are not flushing your buffered writer, so the last stuff you could be incomplete, add flush at end and close all your resources. Debugger is a good idea :)