Two ArrayList can be compared to check if they are equal or not using the method java.util.ArrayList.equals(). This method has a single parameter i.e. an ArrayList that is compared with the current object. It returns true if the two ArrayList are equal and false otherwise.A program that demonstrates this is given as follows −Example Live Demoimport java.util.ArrayList; import java.util.List; public class Demo { public static void main(String[] args) { List aList1 = new ArrayList(); aList1.add("Sun"); aList1.add("Moon"); ... Read More

Clear the IdentityHashMap using the clear() method.Create an IdentityHashMap and add elements to it −Map m = new IdentityHashMap(); m.put("1", 100); m.put("2", 200); m.put("3", 300); m.put("4", 150); m.put("5", 110); m.put("6", 50); m.put("7", 90); m.put("8", 250);Now, let us use the clear() method to remove all the elements −m.clear()The following is an example to remove all elements in IdentityHashMap in Java −Example Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { Map m = new IdentityHashMap(); m.put("1", 100); ... Read More

To get the sub set from TreeSet, use the subSet() method. Let us first create a TreeSet and add elements to it −TreeSet set = new TreeSet(); set.add("78"); set.add("56"); set.add("88"); set.add("54"); set.add("76"); set.add("34");Let us get the subset now from a range of elements −SortedSet sorted = set.subSet("54", "76");The following is an example to get sub set from Java TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet set = new TreeSet(); set.add("78"); set.add("56"); ... Read More

To get the size of TreeSet, use the size() method.Create a TreeSet and add elements to it −TreeSet tSet = new TreeSet(); tSet.add("78"); tSet.add("56"); tSet.add("88"); tSet.add("12");Now, get the size of the TreeSet −tSet.size()The following is an example to get the size of TreeSet in Java −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet tSet = new TreeSet(); tSet.add("78"); tSet.add("56"); tSet.add("88"); tSet.add("12"); ... Read More

To remove the highest element, use the pollLast() method.Create a TreeSet and add elements to it −TreeSet tSet = new TreeSet(); tSet.add("78"); tSet.add("56"); tSet.add("88"); tSet.add("12");Now, remove the highest element −tSet.pollLast()The following is an example to remove highest element in Java TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet tSet = new TreeSet(); tSet.add("78"); tSet.add("56"); tSet.add("88"); tSet.add("12"); ... Read More

To remove the lowest element, use the pollFirst() method.Create a TreeSet and add elements to it −TreeSet tSet = new TreeSet(); tSet.add("78"); tSet.add("56"); tSet.add("88"); tSet.add("12");Now, remove the lowest element −tSet.pollFirst()The following is an example to remove lowest element in Java TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet tSet = new TreeSet(); tSet.add("78"); tSet.add("56"); tSet.add("88"); tSet.add("12"); ... Read More

To get the last value in TreeSet, use the last() method.First, get the TreeSet and add elements to it −TreeSet tSet = new TreeSet(); tSet.add("10"); tSet.add("20"); tSet.add("30"); tSet.add("40"); tSet.add("50"); tSet.add("60");Now, get the first value −tSet.last()The following is an example to get the last value in TreeSet −Example Live Demoimport java.util.*; public class Demo {   public static void main(String args[]){ TreeSet tSet = new TreeSet(); tSet.add("10"); tSet.add("20"); tSet.add("30"); ... Read More

Create a TreeSet and add elements −TreeSet tSet = new TreeSet(); tSet.add("TV"); tSet.add("Radio"); tSet.add("Internet");Now, let us copy it to object array −Object[] arr = tSet.toArray(); for (Object ob: arr) {    System.out.println(ob); }The following is an example to copy all elements in TreeSet to an Object Array −Example Live Demoimport java.util.*; public class Demo {    public static void main(String args[]){       TreeSet tSet = new TreeSet();       tSet.add("TV"); tSet.add("Radio"); tSet.add("Internet"); System.out.println("TreeSet elements = "+tSet); ... Read More

Create a TreeSet and add elements −TreeSet tSet = new TreeSet(); tSet.add("TV"); tSet.add("Radio"); tSet.add("Internet");Iterate through the elements −Iterator i = tSet.iterator(); while(i.hasNext()){ System.out.println(i.next()); }The following is an example to create a TreeSet −Example Live Demoimport java.util.*; public class Demo { public static void main(String args[]){ TreeSet tSet = new TreeSet(); tSet.add("TV"); tSet.add("Radio"); tSet.add("Internet"); Iterator i = tSet.iterator(); while(i.hasNext()){ System.out.println(i.next()); } } }OutputInternet Radio TV

Elements can be filled in a Java long array in a specified range using the java.util.Arrays.fill() method. This method assigns the required long value in the specified range to the long array in Java.The parameters required for the Arrays.fill() method are the array name, the index of the first element to be filled(inclusive), the index of the last element to be filled(exclusive) and the value that is to be stored in the array elements.A program that demonstrates this is given as follows −Example Live Demoimport java.util.Arrays; public class Demo { public static void main(String[] argv) throws Exception { ... Read More