How to use java.util

 for (Map.Entry<String, Object> entry : map.entrySet()) {
  String key = entry.getKey();
  Object value = entry.getValue();
  // ...
}

 Map<String, Object> map = ...;

for (String key : map.keySet()) {
  // ...
}

 public static void printMap(Map mp) {
  Iterator it = mp.entrySet().iterator();
  while (it.hasNext()) {
    Map.Entry pair = (Map.Entry)it.next();
    System.out.println(pair.getKey() + " = " + pair.getValue());
    it.remove(); // avoids a ConcurrentModificationException
  }
}

static void addDefaultInstance(Class<?> clazz, Object o, String tag) {
  List<Object> list = defaultInstances.get(clazz);
  if (list == null) {
    list = new ArrayList<Object>();
    defaultInstances.put(clazz, list);
  }
  list.add(o);
  list.add(tag);
}

 /**
  * Collects the remaining objects of the given iterator into a List.
  * 
  * @return a new List with the remaining objects.
  */
 public static <E> List<E> toList(Iterator<E> iterator) {
  List<E> copy = new ArrayList<>();
  while (iterator.hasNext()) {
   copy.add(iterator.next());
  }
  return copy;
 }
}

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

// This is a clever way to create the iterator and call iterator.hasNext() like
// you would do in a while-loop. It would be the same as doing:
//     Iterator<String> iterator = list.iterator();
//     while (iterator.hasNext()) {
for (Iterator<String> iterator = list.iterator(); iterator.hasNext();) {
  String string = iterator.next();
  if (string.isEmpty()) {
    // Remove the current element from the iterator and the list.
    iterator.remove();
  }
}

 List<String> list = new ArrayList<String>();
//add some stuff
list.add("android");
list.add("apple");
String[] stringArray = list.toArray(new String[0]);

private static Map<String, String> getMap(String prefix) {
  Map<String, String> m = new HashMap<String, String>();
  m.put("firstName", prefix + "First");
  m.put("lastName", prefix + "Last");
  return m;
}

  @Override
  public Collection<String> apply(Integer t1) {
    if (t1 == 2) {
      return new ArrayList<String>();
    } else {
      return new HashSet<String>();
    }
  }
};

TestObservable(CountDownLatch once, CountDownLatch okToContinue, T... values) {
  this.values = Arrays.asList(values);
  this.size = this.values.size();
  this.once = once;
  this.okToContinue = okToContinue;
  this.seed = null;
}

 @Test(expected=IndexOutOfBoundsException.class)
public void testIndexOutOfBoundsException() {
  ArrayList emptyList = new ArrayList();
  Object o = emptyList.get(0);
}

  @Override
  public Iterable<Integer> apply(Integer v) throws Exception {
    if ((v & 1) == 1) {
      return Collections.emptyList();
    }
    return Arrays.asList(1, 2);
  }
})

 Map<String, String> map = ...
for (Map.Entry<String, String> entry : map.entrySet())
{
  System.out.println(entry.getKey() + "/" + entry.getValue());
}

/**
 * An eagerly evaluated stream of customers stored in memory.
 */
@Override
public Stream<Customer> getAll() {
 return idToCustomer.values().stream();
}

 if (!Date.now) {
  Date.now = function() { return new Date().getTime(); }
}

 // These two have the same value
new String("test").equals("test") // --> true 

// ... but they are not the same object
new String("test") == "test" // --> false 

// ... neither are these
new String("test") == new String("test") // --> false 

// ... but these are because literals are interned by 
// the compiler and thus refer to the same object
"test" == "test" // --> true 

// ... but you should really just call Objects.equals()
Objects.equals("test", new String("test")) // --> true
Objects.equals(null, "test") // --> false

 static String convertStreamToString(java.io.InputStream is) {
  java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
  return s.hasNext() ? s.next() : "";
}

 import java.util.TimeZone;

public class Test {
  public static void main(String[] args) throws Exception {
    long startOf1900Utc = -2208988800000L;
    for (String id : TimeZone.getAvailableIDs()) {
      TimeZone zone = TimeZone.getTimeZone(id);
      if (zone.getRawOffset() != zone.getOffset(startOf1900Utc - 1)) {
        System.out.println(id);
      }
    }
  }
}

private static Map<String, String> getMap(String prefix) {
  Map<String, String> m = new HashMap<String, String>();
  m.put("firstName", prefix + "First");
  m.put("lastName", prefix + "Last");
  return m;
}

 var today = new Date();
var dd = today.getDate();
var mm = today.getMonth()+1; //January is 0!
var yyyy = today.getFullYear();

if(dd<10) {
  dd='0'+dd
} 

if(mm<10) {
  mm='0'+mm
} 

today = mm+'/'+dd+'/'+yyyy;
document.write(today);