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#Java - Code Snippets for '#Java.util' - 79 code snippet(s) found

 Sample 1. Combine two Summaries and Generate a new Summary using Lambda Expression

// Populate a List using Set elements.

// Declare and Initialize the Collection

Set<Integer> intSet = new HashSet<Integer>();
Set<Integer> intSet2 = new HashSet<Integer>();

// Add Elements

intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);
intSet2.add(1);
intSet2.add(2);
intSet2.add(3);
intSet2.add(4);

// Use the stream and collectors to Summarize all Integer elements

IntSummaryStatistics summary = intSet.stream().collect(Collectors.summarizingInt(p->((Integer)p)));

summary.combine(intSet2.stream().collect(Collectors.summarizingInt(p->((Integer)p))));

System.out.println(summary); // Prints IntSummaryStatistics{count=8, sum=20, min=1, average=2.500000, max=4}

   Like      Feedback     lambda expression   collections   set  hashset  generics  stream   collectors   Collectors.summarizingInt   summary.combine  java.util.hashset  java.util.stream.Collectors  java.util.IntSummaryStatistics


 Sample 2. Get all elements greater than 2, sort them and then push them to a new set, using Lambda Expression

// Declare and Initialize the Collection

Set<Integer> intSet = new HashSet<Integer>();

// Add Elements

intSet.add(1);
intSet.add(2);
intSet.add(3);
intSet.add(4);

// Set the predicate or the condition for filtering the elements.

Predicate<Integer> moreThan2Pred = (p) -> (p > 1);

// Use Filter to refine the element set, sort to Sort and Collectors.toSet to get a set out of Stream.

intSet = intSet.stream().filter(moreThan2Pred).sorted().collect(Collectors.toSet());

System.out.println(intSet); // Prints [2, 3, 4]

   Like      Feedback     lambda expression   collections   set  hashset  generics  stream   predicate   filter   sort  java.util.hashset  java.util.stream.Collectors


 Sample 3. Scheduling task using java.util.timer

static {
timer.schedule(new ScheduledTask(), 60000, 60000);
}

private static class Schedule extends TimerTask {
@Override public void run() {
//doSomething();
}
}

   Like      Feedback     java.util.timer  java.util.TimerTask  scheduling task  java.lang  Override


 Sample 4. Usage of LinkedHashMap


Map<String,String> linkedhashmap = new LinkedHashMap();
linkedhashmap.put("United States", "Washington");
linkedhashmap.put("Canada", "Ottawa");
linkedhashmap.put("Canada", "Ottawa");
linkedhashmap.put("South Africa", "Pretoria");
linkedhashmap.put("South Africa", "Cape Town");
linkedhashmap.put("South Africa", "Bloemfontein");

System.out.println(linkedhashmap); // Duplicates not allowed as it's a Map, Insertion Order as its linked Map

   Like      Feedback     LinkedHashMap  Map  HashMap  java.util  collections framework


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 Sample 5. Write a Program for Graph Depth First Traversal using Apache Commons MultiMap

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;

public class Graph {
   private static Multimap<Integer,Integer> adjacentDirectedNodesMap = ArrayListMultimap.create();
   private static Set<Integer> alreadyVisited = new HashSet();
   
   static{
      adjacentDirectedNodesMap.put(1, 2);
      adjacentDirectedNodesMap.put(1, 3);
      adjacentDirectedNodesMap.put(1, 5);
      adjacentDirectedNodesMap.put(2, 4);
      adjacentDirectedNodesMap.put(4, 5);
   }
   
   public static void main(String[] args){
      ArrayList visited = new ArrayList();
      
      Integer startNode = 1;
      
      displayAdjacentNodes(startNode);
      
   }
   
   private static void displayAdjacentNodes(Integer integer){
      if(alreadyVisited.contains(integer)){
         return;
      }
      alreadyVisited.add(integer);
      System.out.println(integer);
      for(Integer adjacentNodes: adjacentDirectedNodesMap.get(integer)){
         displayAdjacentNodes(adjacentNodes);
      }
   }
   
}

   Like      Feedback     graph traversal  depth first algorithm


 Sample 6. Java Code to get all images url from html code.

regex = Pattern.compile("[http]");
regexMatcher = regex.matcher(htmlParseData.getHtml());
List tr=htmlParseData.getOutgoingUrls();
imgUrlCounter=0;
for(i=0;i<tr.size();i++){
if(tr.get(i).toString().contains(".jpg") || tr.get(i).toString().contains(".jpeg") || tr.get(i).toString().contains(".gif") || tr.get(i).toString().contains(".bmp")){
url = new URL(tr.get(i).toString());
Image image = new ImageIcon(url).getImage();
}
}

   Like      Feedback     regex  pattern  regex.matcher  html  java.util.regex.pattern  regular expressions


 Sample 7. Code to find email ids in a string using Pattern.

String text="vivek boy goy vivek@tech.com viv@ek.com sdjs@adjk";
Pattern regex = Pattern.compile("[@]");
Matcher regexMatcher = regex.matcher(text);
int i =0;
int width = 0;
while (regexMatcher.find()) {
if((regexMatcher.start()-10 > 0) && (regexMatcher.end()+10 < text.length())){
width=10;
String[] substr=text.substring(regexMatcher.start()-width,regexMatcher.end()+width).split(" ");
for(int j=0;j<substr.length;j++){
if(substr[j].contains("@") && (substr[j].contains(".com") || substr[j].contains(".net"))){
System.out.println(substr[j]);
}
}
} else {
width=0;
}
}

   Like      Feedback     regex  pattern  string  regexMatcher.find  java.util.regex.Matcher  java.util.regex.Pattern


 Sample 8. Usage of HashMap

Map<Integer,String> indexedInfo = new HashMap();
indexedInfo.put(1,"Spain");
indexedInfo.put(2,"Denmark");
indexedInfo.put(3,"China");

   Like      Feedback     hashmap  map  collections  java.util.hashmap


 Sample 9. Enum with a method to get the constant having specific member element.

public enum JavaFramework {
SPRING("Spring","Web"),
STRUTS("Struts","Web"),
JSF("JSF","View"),
CRUNCH("Apache Crunch","BigData");


public String name;
public String type;

JavaFramework(String name, String type){
this.name = name;
this.type = type;
}

static public List<JavaFramework> getByType(String type) {
List<JavaFramework> frameworks = new ArrayList();
for(JavaFramework framework: JavaFramework.values()){
if(framework.type.equalsIgnoreCase(type)){
frameworks.add(framework);
}
}

return frameworks;
}
}

   Like      Feedback     enum  java.util.list


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 Sample 10. Blogger API for creating Posts ( Change xxxxxx to your blog specific info )

package Reader;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import com.squareup.okhttp.MediaType;
import com.squareup.okhttp.OkHttpClient;

public class BlogPostCreater {

public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");

OkHttpClient client = new OkHttpClient();

String post(String title, String content,String label,String authorization_key) throws IOException {

content = content.replace(""",""");


String url = "https://www.googleapis.com/blogger/v3/blogs/xxxxxxxxxx/posts?clientId=xxxxxxxx&clientSecret=xxxxxxxx";

HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);

// add header
post.setHeader("Authorization", authorization_key);
post.setHeader("Content-type","application/json");

post.setEntity(new StringEntity(buildJson(title,content,label)));

HttpResponse response = client.execute(post);

System.out.println(response);

return "true";
}



String buildJson(String title, String content,String label) {

System.out.println(label);
return "{"status": "LIVE", "content": ""+content+"", "kind": "blogger#post"" +
", "title": ""+title+"", "url": "xxxxxx", " +
""readerComments": "DONT_ALLOW_HIDE_EXISTING", "author": {" +
""url": "https://www.blogger.com/profile/04326686331881561093", " +
""image": {" +
""url": "//lh4.googleusercontent.com/-64Ucx9lX9Q4/AAAAAAAAAAI/AAAAAAAAAx0/-rUjBgS3djE/s35-c/photo.jpg"" +
"}, " +
""displayName": "Vivek Vermani", " +
""id": "g108356395081185480077"" +
"}, "updated": "2015-09-28T09:46:12+05:30", "replies": {"totalItems": "0", " +
""selfLink": "https://www.googleapis.com/blogger/v3/blogs/xxxxxxxxxx/posts/2495464003469367152/comments"" +
"}, "blog": {"id": "4275342475651800664"}, " +
""etag": "'GtyIIQmNmmUjEA0nwhSqMElCJ1g/dGltZXN0YW1wOiAxNDQzNDEzNzcyMDc1Cm9mZnNldDogMTk4MDAwMDAK'", " +
""published": "2015-09-28T09:46:00+05:30", " +
""id": "2495464003469367152", " +
""selfLink": "https://www.googleapis.com/blogger/v3/blogs/xxxxxx/posts/2495464003469367152"}";
}

public String post(String url, Map<String,String> formParameters) throws ClientProtocolException, IOException {
HttpPost request = new HttpPost(url);

List <NameValuePair> nvps = new ArrayList <NameValuePair>();

for (String key : formParameters.keySet()) {
nvps.add(new BasicNameValuePair(key, formParameters.get(key)));
}

request.setEntity(new UrlEncodedFormEntity(nvps));

return execute(request);
}

// makes request and checks response code for 200
private String execute(HttpRequestBase request) throws ClientProtocolException, IOException {
HttpClient httpClient = new DefaultHttpClient();
HttpResponse response = httpClient.execute(request);

HttpEntity entity = response.getEntity();
String body = EntityUtils.toString(entity);

if (response.getStatusLine().getStatusCode() != 200) {
throw new RuntimeException("Expected 200 but got " + response.getStatusLine().getStatusCode() + ", with body " + body);
}

return body;
}


}

   Like      Feedback     blogger api   blogger api for post creation  java.lang.RuntimeException


 Sample 11. Sort a List using Collections.sort and comparator

Collections.sort(listClassInfo,new Comparator<ClassInfoBean>(){
public int compare(ClassInfoBean s1,ClassInfoBean s2){
if(s1.name.compareTo(s2.name) < 0){
return -1;
} else {
return 1;
}

}});

   Like      Feedback     sorting   sort   Collections.sort   sort a list   comparator   compare method  java.util.Collections


 Sample 12. ArrayList of Optional Integers

List<Optional<Integer>> intList = new ArrayList<Optional<Integer>>();

// Add Elements

intList.add(Optional.empty());
intList.add(Optional.of(2));
intList.add(Optional.of(3));
intList.add(Optional.of(4));

   Like      Feedback     optional  java 8   list   arraylist   list of optional integers   arraylist of optional  java.util.Optional


 Sample 13. Get current time using GregorianCalendar

Calendar calendar = new GregorianCalendar();
float currentTime = calendar.get( Calendar.HOUR_OF_DAY ) + ((float)calendar.get( Calendar.MINUTE )/100);

   Like      Feedback     GregorianCalendar  Calendar.HOUR_OF_DAY  Calendar.MINUTE  Calendar.java.util.Calendar


 Sample 14. Initialize java.util.date using java.util.Calendar

Date currentDate = Calendar.getInstance().getTime();

   Like      Feedback     calendar  java.util.calendar  java.util  date  java.util.date  Calendar.getTime


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 Sample 15. Initialize list using google guava Lists

import java.util.List;
import com.google.common.collect.Lists;

class GoogleListsTest{
public static void main(String[] args){
List list = Lists.newArrayList();
}
}

   Like      Feedback     list  google guava  Lists  Lists.newArrayList  com.google.common.collect.Lists


 Sample 16. Write a Program for coin changer application. The program should set the cash box with available currency and then should render the exact change. If enough cash is not available , it should present the appropriate message.

import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;


public class CoinChanger {

enum Currency {
DOLLAR(1),QUARTER(.25),DIME(.10),NICKEL(.05),PENNY(.01);

private double currencyValue;

Currency(double value){
currencyValue = value;
}

double getCurrencyValue(){
return this.currencyValue;
}
}

private static Map<Currency, Integer> cashBox;
private static Map<Currency, Integer> change;

static {
cashBox = new TreeMap<Currency, Integer>();
change = new TreeMap<Currency, Integer>();
initializeCashBox();
}



public static void main(String[] args) {
double amountToReturn = 18.79f; // Set the amount to be changed here

for(Entry<Currency, Integer> entry:cashBox.entrySet()){
Currency currency = (Currency)entry.getKey();
int coinCount = (int)(amountToReturn/(entry.getKey().getCurrencyValue()));
int availableCurrency = (int)(entry.getValue());

if(coinCount > availableCurrency){
coinCount = availableCurrency;
}

change.put(currency, coinCount);
if(coinCount > 0){
amountToReturn = amountToReturn - (coinCount * entry.getKey().getCurrencyValue());
}
}

System.out.println(change);

if(amountToReturn > .1){
System.out.println("Not enough cash");
}
}

private static void initializeCashBox(){
//set the cash box
cashBox.put(Currency.DOLLAR, 50);
cashBox.put(Currency.QUARTER, 0);
cashBox.put(Currency.DIME, 50);
cashBox.put(Currency.NICKEL, 50);
cashBox.put(Currency.PENNY, 50);

}
}

   Like      Feedback     coin changer application  coin changer app


 Sample 17. Method to get Date after n days using Calendar

Date getDateAfterDays(int numberOfDays){
   Calendar futureDate = Calendar.getInstance();
   futureDate.setTime(new Date()); // Set Current Date
   futureDate.add(Calendar.DATE, numberOfDays); // Add n days to current Date

   return new Date(futureDate.getTimeInMillis());
}

   Like      Feedback     date   calendar   java.util  calendar.add  calendar.date  calendar.settime  calendar.gettimeinmillis


 Sample 18. Get Date and Time after few Hours

Date getDateTimeAfterNHours(int numberOfHours){
   Calendar futureTime = Calendar.getInstance();
   futureTime.setTime(new Date()); // Set Current Date
   futureTime.add(Calendar.HOUR, numberOfDays); // Add n hours to current Date and Time

   return new Date(futureTime.getTimeInMillis());
}

   Like      Feedback     date   calendar   java.util  calendar.add  calendar.hour  calendar.settime  calendar.gettimeinmillis


 Sample 19. Convert Time in milliseconds to Days

TimeUnit.DAYS.convert(timeinMs, TimeUnit.MILLISECONDS)

   Like      Feedback     convert time in ms to days  TimeUnit  java.util.concurrent.TimeUnit


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 Sample 20. Time Taken to call a method or service

Date date1 = new Date();

// Call Service or Method

Date date2 = new Date();
System.out.println(TimeUnit.SECONDS.convert(date2.getTime()-date1.getTime(), TimeUnit.MILLISECONDS));// Time Taken in Seconds
System.out.println(TimeUnit.MINUTES.convert(date2.getTime()-date1.getTime(), TimeUnit.MILLISECONDS));// Time Taken in Minutes
System.out.println(TimeUnit.HOURS.convert(date2.getTime()-date1.getTime(), TimeUnit.MILLISECONDS));// Time Taken in Hours

   Like      Feedback     Difference between 2 dates  Time to call a method  TimeUnit  Date.java.util.Date


 Sample 21. Spring AMQP ( messaging-rabbitmq ) - Register the listener and send a message

https://spring.io/guides/gs/messaging-rabbitmq/

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 Sample 22. RabbitMQ message receiver

import java.util.concurrent.CountDownLatch;

public class Receiver {

   private CountDownLatch latch = new CountDownLatch(1);

   public void receiveMessage(String message) {
      latch.countDown();
   }

   public CountDownLatch getLatch() {
      return latch;
   }

}

   Like      Feedback     Spring AMQP  Rabbit MQ  RabbitMQ


 Sample 23. Apache Kafka Producer

https://apache.googlesource.com/kafka/+/trunk/examples/src/main/java/kafka/examples/Producer.java

   Like      Feedback     


 Sample 24. Implementation of NamespaceContext

import java.util.Iterator;

import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;

// Map prefixes to Namespace URIs
public class APINameSpaceContext implements NamespaceContext
{
   static final String WEB_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/web";
   static final String API_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/element";
   static final String SPELL_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/spell";
   static final String RS_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/relatedsearch";
   static final String PB_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/phonebook";
   static final String MM_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/multimedia";
   static final String AD_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/ads";
   static final String IA_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/instantanswer";
   static final String NEWS_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/news";
   static final String ENCARTA_NAMESPACE = "http://schemas.microsoft.com/LiveSearch/2008/04/XML/encarta";

   public String getNamespaceURI(String prefix)
   {
      if (prefix == null) throw new NullPointerException("Null prefix");
      else if ("api".equals(prefix)) return API_NAMESPACE;
      else if ("web".equals(prefix)) return WEB_NAMESPACE;
      return XMLConstants.NULL_NS_URI;
   }
   
   // This method isn't necessary for XPath processing.
   public String getPrefix(String uri)
   {
      throw new UnsupportedOperationException();
   }
   
   public Iterator getPrefixes(String arg0)
   {
      throw new UnsupportedOperationException();
   }
}

   Like      Feedback     NamespaceContext


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 Sample 25. Apache Hadoop Map Reduce Example

https://apache.googlesource.com/hadoop-common/+/trunk/hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/Grep.java

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 Sample 26. Apache Hadoop Multi File Word Count

https://apache.googlesource.com/hadoop-common/+/trunk/hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/MultiFileWordCount.java

   Like      Feedback     


 Sample 27. Usage of org.apache.abdera.model.Entry;

Entry entry = factory.newEntry();
entry.setId(FOMHelper.generateUuid());
entry.setUpdated(new java.util.Date());
entry.addAuthor("James");
entry.setTitle("Posting to Roller");
entry.setContentAsHtml("<p>This is an example post to Roller</p>");
AbderaClient abderaClient = new AbderaClient(abdera);
abderaClient.addCredentials(start, null, null, new UsernamePasswordCredentials("username", "password"));
Document<Service> service_doc = abderaClient.get(start).getDocument();
Service service = service_doc.getRoot();
Collection collection = service.getWorkspaces().get(0).getCollections().get(0);
String uri = collection.getHref().toString();
Response response = abderaClient.post(uri, entry);

   Like      Feedback     


 Sample 28. Internal Implementation of ArrayList#removeIf

@Override
public boolean removeIf(Predicate<? super E> filter) {
Objects.requireNonNull(filter);

int removeCount = 0;
final BitSet removeSet = new BitSet(size);
final int expectedModCount = modCount;
final int size = this.size;
for (int i=0; modCount == expectedModCount && i < size; i++) {
@SuppressWarnings("unchecked")
final E element = (E) elementData[i];
if (filter.test(element)) {
removeSet.set(i);
removeCount++;
}
}
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}

// shift surviving elements left over the spaces left by removed elements
final boolean anyToRemove = removeCount > 0;
if (anyToRemove) {
final int newSize = size - removeCount;
for (int i=0, j=0; (i < size) && (j < newSize); i++, j++) {
i = removeSet.nextClearBit(i);
elementData[j] = elementData[i];
}
for (int k=newSize; k < size; k++) {
elementData[k] = null; // Let gc do its work
}
this.size = newSize;
if (modCount != expectedModCount) {
throw new ConcurrentModificationException();
}
modCount++;
}

return anyToRemove;
}

   Like      Feedback     Internal Implementation of ArrayList#removeIf  java.util.function.Predicate  java.util.Objects  java.util.Objects  java.util.ConcurrentModificationException.ConcurrentModificationException


 Sample 29. Internal Implementation of BufferedReader#lines

public Stream<String> lines() {
Iterator<String> iter = new Iterator<String>() {
String nextLine = null;

@Override
public boolean hasNext() {
if (nextLine != null) {
return true;
} else {
try {
nextLine = readLine();
return (nextLine != null);
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
}

@Override
public String next() {
if (nextLine != null || hasNext()) {
String line = nextLine;
nextLine = null;
return line;
} else {
throw new NoSuchElementException();
}
}
};
return StreamSupport.stream(Spliterators.spliteratorUnknownSize(
iter, Spliterator.ORDERED | Spliterator.NONNULL), false);
}

   Like      Feedback     Internal Implementation of BufferedReader#lines


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 Sample 30. Usage of org.joda.time.DateMidnight

DateMidnight currentDate = new DateMidnight();
DateMidnight dateafterAMonth = currentDate.plusMonths(1);
Date javaSedateAfterAMonth = dateafterAMonth.toDate();

   Like      Feedback     org.joda.time.DateMidnight  java.util.Date  Date  Add month to Date


 Sample 31. Check whether a reference of AbstractCollection holds a List,Queue or Set

public static void main(String[] args)  {
      
       AbstractCollection collection = new ArrayList();
      
       if(collection instanceof AbstractList){
          System.out.println("This is a list");
       }
      
       if(collection instanceof AbstractQueue){
          System.out.println("This is a Queue");
       }
      
       if(collection instanceof AbstractSet){
          System.out.println("This is a Set");
       }
      
}

   Like      Feedback     instaceOf  AbstractCollection


 Sample 32. Clear Map entries after expiration time using Apache commons PassiveExpiringMap

PassiveExpiringMap<String,String> cache = new PassiveExpiringMap<String,String>(1,TimeUnit.SECONDS); // Expiration time of 1 sec
cache.put("Key1", "Value1");
System.out.println(cache.containsKey("Key1")); // prints true
Thread.sleep(1000);
System.out.println(cache.containsKey("Key1")); // prints false

   Like      Feedback     Clear Map entries after expiration  PassiveExpiringMap  map  apache commons  TimeUnit.SECONDS  Thread.sleep


 Sample 33. Make a map readonly using Apache Commons UnmodifiableMap

Map<String,String> map = new HashMap();
map.put("Key1", "Value1");

Map<String,String> unmodifiableMap = UnmodifiableMap.unmodifiableMap(map);
      
unmodifiableMap.put("Key2", "Value2"); // throws java.lang.UnsupportedOperationException

   Like      Feedback     readonly map  apache commons


 Sample 34. Usage of TreeMap

Map<String,String> treemap = new TreeMap();
treemap.put("United States", "Washington");
treemap.put("Canada", "Ottawa");
treemap.put("Canada", "Ottawa");
treemap.put("South Africa", "Pretoria");
treemap.put("South Africa", "Cape Town");
treemap.put("South Africa", "Bloemfontein");

System.out.println(treemap); // Duplicate Not allowed as it's a Map, Ordered by Keys as it's a TreeMap

   Like      Feedback     TreeMap  Map  java.util


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 Sample 35. Usage of ConcurrentSkipListMap

Map<String,String> map = new ConcurrentSkipListMap();
map.put("United States", "Washington");
map.put("Canada", "Ottawa");
map.put("Canada", "Ottawa");
map.put("South Africa", "Pretoria");
map.put("South Africa", "Cape Town");
map.put("South Africa", "Bloemfontein");

System.out.println(map); // Prints {Canada=Ottawa, South Africa=Bloemfontein, United States=Washington}
      
// Duplicates not allowed as it's a Map, Sorted as par natural order of keys for faster and concurrent operations.

   Like      Feedback     map  ConcurrentSkipListMap  concurrent access map


 Sample 36. Usage of EnumMap

Map<Country,String> map = new HashMap();
map.put(Country.US, "Washington");
map.put(Country.CANADA, "Ottawa");
map.put(Country.CANADA, "Ottawa");
map.put(Country.SOUTH_AFRICA, "Pretoria");
map.put(Country.SOUTH_AFRICA, "Cape Town");
map.put(Country.SOUTH_AFRICA, "Bloemfontein");

Map<String,String> enumMap = new EnumMap(map); // Prints {CANADA=Ottawa, US=Washington, SOUTH_AFRICA=Bloemfontein}

System.out.println(enumMap); // Duplicates not allowed as it's a Map, Sorted as per order of Enum Declarations

   Like      Feedback     EnumMap  Collections framework  Map  Map with enum keys


 Sample 37. Get the Date object using the TimeZone

TimeZone zone = (TimeZone.getDefault().getRawOffset() == EET.getRawOffset() ? EST : EET);
Date expectedZone = createCalendar(zone, 20051231, 0).getTime();

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 Sample 38. Generate Random Number till 100

Random rand = new Random();
int randomNumber = rand.nextInt(100);

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 Sample 39. Usage of java.text.NumberFormat

NumberFormat formatter = null;
if (locale != null) {
formatter = NumberFormat.getNumberInstance(locale);
} else {
formatter = NumberFormat.getNumberInstance(Locale.getDefault());
}

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 Sample 40. Usage of Java Collections Stack

Stack<INodeDirectory> directories = new Stack<INodeDirectory>();
for(directories.push((INodeDirectory)inode); !directories.isEmpty(); ) {
   INodeDirectory d = directories.pop();
}

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 Sample 41. Usage of java.util.concurrent.Future

long bytesLastMoved = bytesMoved.get();
Future<?>[] futures = new Future<?>[sources.size()];
int i=0;
for (Source source : sources) {
   futures[i++] = dispatcherExecutor.submit(source.new BlockMoveDispatcher());
}

for (Future<?> future : futures) {
   try {
      future.get();
   } catch (ExecutionException e) {
      LOG.warn("Dispatcher thread failed", e.getCause());
   }
}

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 Sample 42. Code Sample / Example / Snippet of java.util.StringTokenizer

  public static List<String> getNamedOutputsList(JobConf conf) {

List<String> names = new ArrayList<String>();

StringTokenizer st = new StringTokenizer(conf.get(NAMED_OUTPUTS, ""), " ");

while (st.hasMoreTokens()) {

names.add(st.nextToken());

}

return names;

}


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 Sample 43. Code Sample / Example / Snippet of java.util.Calendar

    public static double year()

{

Calendar cal = Calendar.getInstance();

return cal.get(Calendar.YEAR);

}


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 Sample 44. Code Sample / Example / Snippet of java.util.zip.DeflaterOutputStream

    private byte[] deflate(byte[] b) throws IOException {

ByteArrayOutputStream baos = new ByteArrayOutputStream();

DeflaterOutputStream dos = new DeflaterOutputStream(baos);

dos.write(b);

dos.close();

return baos.toByteArray();

}


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 Sample 45. Code Sample / Example / Snippet of java.util.EventListener

    private void readObject(ObjectInputStream s)

throws IOException, ClassNotFoundException {

listenerList = NULL_ARRAY;

s.defaultReadObject();

Object listenerTypeOrNull;



while (null != (listenerTypeOrNull = s.readObject())) {

ClassLoader cl = Thread.currentThread().getContextClassLoader();

EventListener l = (EventListener)s.readObject();

String name = (String) listenerTypeOrNull;

ReflectUtil.checkPackageAccess(name);

add((Class<EventListener>)Class.forName(name, true, cl), l);

}

}




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 Sample 46. Concatenate two Streams

public static IntStream concat(IntStream a, IntStream b) {
Objects.requireNonNull(a);
Objects.requireNonNull(b);

Spliterator.OfInt split = new Streams.ConcatSpliterator.OfInt(
a.spliterator(), b.spliterator());
IntStream stream = StreamSupport.intStream(split, a.isParallel() || b.isParallel());
return stream.onClose(Streams.composedClose(a, b));
}

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 Sample 47. Code Sample / Example / Snippet of java.util.Map

  public Schema create(SchemaPlus parentSchema, String name,

Map<String, Object> operand) {

Map map = (Map) operand;

String host = (String) map.get("host");

String database = (String) map.get("database");

return new MongoSchema(host, database);

}


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 Sample 48. Code Sample / Example / Snippet of java.util.Random

  public Enumerable<Object[]> scan(DataContext root) {

final Random random = seed >= 0 ? new Random(seed) : new Random();

final Maze maze = new Maze(width, height);

final PrintWriter pw = new PrintWriter(System.out);

maze.layout(random, pw);

if (Maze.DEBUG) {

maze.print(pw, true);

}

return new AbstractEnumerable<Object[]>() {

public Enumerator<Object[]> enumerator() {

final Set<Integer> solutionSet;

if (solution) {

solutionSet = maze.solve(0, 0);

} else {

solutionSet = null;

}

return Linq4j.transform(maze.enumerator(solutionSet),

new Function1<String, Object[]>() {

public Object[] apply(String s) {

return new Object[] {s};

}

});

}

};

}


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 Sample 49. Code Sample / Example / Snippet of java.util.zip.GZIPInputStream

  private static CSVReader openCsv(File file) throws IOException {

final Reader fileReader;

if (file.getName().endsWith(".gz")) {

final GZIPInputStream inputStream =

new GZIPInputStream(new FileInputStream(file));

fileReader = new InputStreamReader(inputStream);

} else {

fileReader = new FileReader(file);

}

return new CSVReader(fileReader);

}


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 Sample 50. Code Sample / Example / Snippet of java.util.TimeZone

  private static final FastDateFormat TIME_FORMAT_TIMESTAMP;



static {

TimeZone gmt = TimeZone.getTimeZone("GMT");

TIME_FORMAT_DATE = FastDateFormat.getInstance("yyyy-MM-dd", gmt);

TIME_FORMAT_TIME = FastDateFormat.getInstance("HH:mm:ss", gmt);

TIME_FORMAT_TIMESTAMP =

FastDateFormat.getInstance("yyyy-MM-dd HH:mm:ss", gmt);

}


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 Sample 51. Code Sample / Example / Snippet of java.util.Calendar

  private SparkHandlerImpl() {

classServer = new HttpServer(CLASS_DIR);



classServer.start();

System.setProperty("spark.repl.class.uri", classServer.uri());



final Calendar calendar = Calendar.getInstance();

classId = new AtomicInteger(

calendar.get(Calendar.HOUR_OF_DAY) * 10000

+ calendar.get(Calendar.MINUTE) * 100

+ calendar.get(Calendar.SECOND));

}


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 Sample 52. Code Sample / Example / Snippet of java.util.regex.Matcher

    private void defineVariables(String line) {

Matcher varDefn = matchesVarDefn.matcher(line);

if (varDefn.lookingAt()) {

String var = varDefn.group(1);

String val = varDefn.group(2);

vars.define(var, val);

} else {

String[] words = splitWords.split(line);

for (String var : words) {

String value = System.getenv(var);

vars.define(var, value);

}

}

}


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 Sample 53. Code Sample / Example / Snippet of java.util.StringTokenizer

    private List<String> tokenize(String s) {

List<String> result = new ArrayList<>();

StringTokenizer tokenizer = new StringTokenizer(s);

while (tokenizer.hasMoreTokens()) {

result.add(tokenizer.nextToken());

}

return result;

}


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 Sample 54. Code Sample / Example / Snippet of java.util.Collection

      public Void apply(ResultSet resultSet) {

++executeCount;

try {

final Collection result =

CalciteAssert.toStringList(resultSet,

ordered ? new ArrayList<String>() : new TreeSet<String>());

if (executeCount == 1) {

expected = result;

} else {

if (!expected.equals(result)) {

assertThat(newlineList(result), equalTo(newlineList(expected)));

fail("oops");

}

}

return null;

} catch (SQLException e) {

throw new RuntimeException(e);

}

}


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 Sample 55. Code Sample / Example / Snippet of java.util.Properties

    public Connection createConnection() throws SQLException {

final Properties info = new Properties();

for (Map.Entry<String, String> entry : map.entrySet()) {

info.setProperty(entry.getKey(), entry.getValue());

}

Connection connection =

DriverManager.getConnection("jdbc:calcite:", info);

for (ConnectionPostProcessor postProcessor : postProcessors) {

connection = postProcessor.apply(connection);

}

return connection;

}


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 Sample 56. Code Sample / Example / Snippet of java.util.BitSet

    public static BitSet INIT_BITSET(final int ... b) {

final BitSet bitset = new BitSet();

for (final int aB : b) {

bitset.set(aB);

}

return bitset;

}


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 Sample 57. Code Sample / Example / Snippet of java.util.List

    private static List convertArrayToList(Object array)

{

int len = Array.getLength(array);

List list = new ArrayList(len);

for (int i = 0; i < len; i++)

{

list.add(Array.get(array, i));

}

return list;

}


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 Sample 58. Code Sample / Example / Snippet of java.util.regex.Pattern

    private long getStoreId(File storeFile) {

Pattern p = Pattern.compile(m_name + "-(\d+)");

Matcher m = p.matcher(storeFile.getName());

if (m.find()) {

return Long.parseLong(m.group(1));

}

throw new RuntimeException("Invalid store file name: " + storeFile.getName());

}




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 Sample 59. Code Sample / Example / Snippet of java.util.concurrent.ScheduledExecutorService

    public void postEvent(final String topic, Map<String, String> payload) {

final Map<String, String> eventPayload = new HashMap<>(payload);

for (final EventListener listener : m_listeners) {

ScheduledExecutorService executor = getExecutorService();

if (executor.isShutdown()) {

logWarning("Cannot post event, executor is shut down!");

return;

}

executor.submit(new Runnable() {

@Override

public void run() {

try {

listener.handle(topic, eventPayload);

}

catch (Exception e) {

logWarning("Exception while posting event", e);

}

}

});

}

}


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 Sample 60. Code Sample / Example / Snippet of java.util.concurrent.locks.Lock

    public int getDeploymentVersionLimit() {

Lock lock = m_lock.readLock();

lock.lock();

try {

return m_deploymentVersionLimit;

}

finally {

lock.unlock();

}

}


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 Sample 61. Code Sample / Example / Snippet of java.util.Iterator

    public void validateRangeIterators() {

SortedRangeSet srs1 = new SortedRangeSet("1-10");

Iterator i1 = srs1.rangeIterator();

assert i1.hasNext() : "We should have one Range instance in our iterator.";

assert ((Range) i1.next()).toRepresentation().equals("1-10");

assert !i1.hasNext() : "There should be only one instance in our iterator.";

SortedRangeSet srs2 = new SortedRangeSet("1-5,8,10-15");

Iterator i2 = srs2.rangeIterator();

assert i2.hasNext() && i2.next() instanceof Range

&& i2.hasNext() && i2.next() instanceof Range

&& i2.hasNext() && i2.next() instanceof Range

&& !i2.hasNext() : "There should be exactly three Range instances in our iterator.";

SortedRangeSet srs3 = new SortedRangeSet("");

assert !srs3.iterator().hasNext() : "Iterator should be empty.";

}


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 Sample 62. Code Sample / Example / Snippet of java.util.Set

    public Set getExtendList() {

Set set = new HashSet();

for (Iterator i = requirements.iterator(); i.hasNext();) {

RequirementImpl impl = (RequirementImpl) i.next();

if (impl.isExtend())

set.add(impl);

}

return set;

}


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 Sample 63. Code Sample / Example / Snippet of java.util.jar.JarOutputStream

    private File createBundle(String symbolicName, String version) throws IOException {

File tmpFile = File.createTempFile("tmpbundle-", "jar");

tmpFile.deleteOnExit();

Manifest manifest = new Manifest();

manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");

if (symbolicName != null) {

manifest.getMainAttributes().putValue(Constants.BUNDLE_SYMBOLICNAME, symbolicName);

}

if (version != null) {

manifest.getMainAttributes().putValue(Constants.BUNDLE_VERSION, version);

}

JarOutputStream target = new JarOutputStream(new FileOutputStream(tmpFile), manifest);

target.close();

return tmpFile;

}


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 Sample 64. Code Sample / Example / Snippet of java.util.Random

    private File createRandomFileWithContent() throws IOException {

OutputStream fileOut = null;

File file = null;

try {

file = FileUtils.createTempFile(null);

fileOut = new FileOutputStream(file);

byte[] byteArray = new byte[12345];

Random randomContentCreator = new Random();

randomContentCreator.nextBytes(byteArray);

fileOut.write(byteArray);



return file;

}

finally {

try {

if (fileOut != null) {

fileOut.close();

}

}

catch (IOException e) {

throw e;

}

}

}


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 Sample 65. Code Sample / Example / Snippet of java.util.StringTokenizer

	public LowestID(String representation) {

try {

StringTokenizer st = new StringTokenizer(representation, ",");

m_targetID = Codec.decode(st.nextToken());

m_storeID = Long.parseLong(st.nextToken());

m_lowestID = Long.parseLong(st.nextToken());

}

catch (NoSuchElementException e) {

throw new IllegalArgumentException("Could not create lowest ID object from: " + representation);

}

}


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 Sample 66. Code Sample / Example / Snippet of java.util.concurrent.CountDownLatch

    public void testTooLongTask() throws Exception {

final CountDownLatch latch = new CountDownLatch(5);



Executer executer = new Executer(new Runnable() {

public void run() {

try {

Thread.sleep(20);

latch.countDown();

}

catch (InterruptedException e) {

e.printStackTrace();

}

}

});

executer.start(10);

assert latch.await(1, TimeUnit.SECONDS);

}


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 Sample 67. Code Sample / Example / Snippet of java.util.Calendar

    private static Calendar getToday() {

Calendar cal = Calendar.getInstance();

cal.set(Calendar.HOUR_OF_DAY, 12);

cal.set(Calendar.MINUTE, 0);

cal.set(Calendar.SECOND, 0);

cal.set(Calendar.MILLISECOND, 0);

return cal;

}


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 Sample 68. Code Sample / Example / Snippet of java.util.concurrent.Semaphore

    private void removeRepository(String instanceName) throws IOException, InterruptedException, InvalidSyntaxException {

Configuration[] configs = listConfigurations("(factory.instance.pid=" + instanceName + ")");

if ((configs != null) && (configs.length > 0)) {

final Semaphore sem = new Semaphore(0);

ServiceTracker<Object, Object> tracker = new ServiceTracker<Object, Object>(m_bundleContext, m_bundleContext.createFilter("(factory.instance.pid=" + instanceName + ")"), null) {

@Override

public void removedService(ServiceReference<Object> reference, Object service) {

super.removedService(reference, service);

sem.release();

}

};

tracker.open();



try {

configs[0].delete();



if (!sem.tryAcquire(1, TimeUnit.SECONDS)) {

throw new IOException("Instance did not get removed in time.");

}

}

finally {

tracker.close();

}

}

}


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 Sample 69. Code Sample / Example / Snippet of java.util.jar.Manifest

    public InputStream getDeploymentPackage(String id, String version) throws OverloadedException, IOException {

List<ArtifactData> data = m_provider.getBundleData(id, version);

Manifest manifest = new Manifest();

Attributes main = manifest.getMainAttributes();



main.putValue("Manifest-Version", "1.0");

main.putValue("DeploymentPackage-SymbolicName", id);

main.putValue("DeploymentPackage-Version", version);



for (ArtifactData bd : data) {

manifest.getEntries().put(bd.getFilename(), bd.getManifestAttributes(false));

}



return DeploymentPackageStream.createStreamForThread(m_connectionFactory, manifest, data.iterator(), false);

}


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 Sample 70. Code Sample / Example / Snippet of java.util.jar.Attributes

    public InputStream getDeploymentPackage(String id, String version) throws OverloadedException, IOException {

List<ArtifactData> data = m_provider.getBundleData(id, version);

Manifest manifest = new Manifest();

Attributes main = manifest.getMainAttributes();



main.putValue("Manifest-Version", "1.0");

main.putValue("DeploymentPackage-SymbolicName", id);

main.putValue("DeploymentPackage-Version", version);



for (ArtifactData bd : data) {

manifest.getEntries().put(bd.getFilename(), bd.getManifestAttributes(false));

}



return DeploymentPackageStream.createStreamForThread(m_connectionFactory, manifest, data.iterator(), false);

}


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 Sample 71. Code Sample / Example / Snippet of java.util.Properties

    public void init(BundleContext context, DependencyManager manager) throws Exception {

manager.add(createComponent()

.setInterface(Servlet.class.getName(), null)

.setImplementation(DeploymentServlet.class)

.add(createConfigurationDependency().setPropagate(true).setPid(DEPLOYMENT_PID))

.add(createServiceDependency().setService(StreamGenerator.class).setRequired(true))

.add(createServiceDependency().setService(DeploymentProvider.class).setRequired(true))

.add(createServiceDependency().setService(DeploymentProcessor.class).setRequired(false).setCallbacks("addProcessor", "removeProcessor"))

.add(createServiceDependency().setService(LogService.class).setRequired(false))

);

manager.add(createComponent()

.setInterface(Servlet.class.getName(), null)

.setImplementation(AgentDeploymentServlet.class)

.add(createConfigurationDependency().setPropagate(true).setPid(AGENT_PID))

.add(createServiceDependency().setService(ConnectionFactory.class).setRequired(true))

.add(createServiceDependency().setService(LogService.class).setRequired(false))

);



Properties props = new Properties();

props.put("pattern", "/*");

manager.add(createComponent()

.setInterface(Filter.class.getName(), null)

.setImplementation(OverloadedFilter.class)

);

}


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 Sample 72. Code Sample / Example / Snippet of java.util.concurrent.ExecutorService

    public void hundredStreamsConcurrently() throws Exception {

ExecutorService e = Executors.newFixedThreadPool(5);

for (int i = 0; i < 10; i++) {

e.execute(new Runnable() {

public void run() {

for (int i = 0; i < 10; i++) {

try {

isJarInputStreamReadable();

}

catch (Exception e) {

m_failure = e;

}

}

}

});

}

e.shutdown();

e.awaitTermination(10, TimeUnit.SECONDS);



assert m_failure == null : "Test failed: " + m_failure.getLocalizedMessage();

}




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 Sample 73. Code Sample / Example / Snippet of java.util.Timer

    public void shutdown(long delay) {

Timer timer = new Timer();

timer.schedule(new TimerTask() {

@Override

public void run() {

try {

m_context.getBundle(0).stop();

}

catch (BundleException e) {

e.printStackTrace();

}

}

}, delay);

}


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 Sample 74. Code Sample / Example / Snippet of java.util.Vector

    private static final String DEFAULT_PROPERTIES_FILE = "QueueMonitor.properties";



String propertiesFile = DEFAULT_PROPERTIES_FILE;

String broker = "tcp://localhost:61616";

String connectID = "QueueMonitor";

String username = "QueueMonitor";

String password = "QueueMonitor";

String browseQueues = "Q1,Q2,Q3";

String textFontName = "Dialog";

String textFontStyle = "PLAIN";

String textFontSize = "12";

String title = "QueueMonitor";



JTextArea textArea = new JTextArea();

JScrollPane scrollPane = new JScrollPane(textArea);

JButton browseButton = new JButton("Browse Queues");



Vector theQueues = new Vector();


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 Sample 75. Write CSV values to a file using au.com.bytecode.opencsv.CSVWriter

String[] stringArray1 = new String[5];
String[] stringArray2 = new String[5];
String[] stringArray3 = new String[5];

List listOfStringArrays = new ArrayList();
listOfStringArrays.add(stringArray1);
listOfStringArrays.add(stringArray2);
listOfStringArrays.add(stringArray3);

File file = new File("BuggyBread.txt");
CSVWriter csvWriter = null;
try {
   csvWriter = new CSVWriter(new FileWriter(file),CSVWriter.DEFAULT_SEPARATOR);
} catch (Exception ex){
}
csvWriter.writeAll(listOfStringArrays);

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 Sample 76. Usage of java.util.stream.Stream

List<Integer> list1 = Arrays.asList(1, 2);
List<Integer> list2 = Arrays.asList(4, 5);

Stream.of(list1, list1)
.flatMap(list -> list.stream())
.forEach(System.out::println);

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 Sample 77. Usage of Java 8 Consumer interface

Consumer<String> consumer = s->{
   System.out.println(s);
};

consumer.accept("BuggyBread"); // prints BuggyBread

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 Sample 78. Usage of java.util.function.BiPredicate

BiPredicate<String, String> predicate = (s1, s2) -> (s1.equals(s2));

System.out.println(predicate.test("BUGGY", "BREAD"));

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 Sample 79. Write a Program for Graph Breadth First Traversal using Apache Commons MultiMap

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;

public class Graph {
   private static Multimap<Integer,Integer> adjacentDirectedNodesMap = ArrayListMultimap.create();
   private static Set<Integer> alreadyVisited = new HashSet();
   
   static{
      adjacentDirectedNodesMap.put(1, 2);
      adjacentDirectedNodesMap.put(1, 3);
      adjacentDirectedNodesMap.put(1, 5);
      adjacentDirectedNodesMap.put(2, 4);
      adjacentDirectedNodesMap.put(4, 5);
   }
   
   public static void main(String[] args){
      ArrayList visited = new ArrayList();
      
      Integer startNode = 1;
      
      displayAdjacentNodes(startNode);
      
   }
   
   private static void displayAdjacentNodes(Integer integer){
      System.out.println(integer);
      for(Map.Entry<Integer, Collection<Integer>> adjacentNodes: adjacentDirectedNodesMap.asMap().entrySet()){
         for(Integer integer1:adjacentNodes.getValue()){
            if(alreadyVisited.contains(integer1)){
               continue;
            }
            alreadyVisited.add(integer1);
            System.out.println(integer1);
         }
      }
   }
   
}

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