The file attribute can be changed to writable using the method java.io.File.setWritable(). This method has a single parameter i.e. a boolean value that if true allows the file to be writable and if false disallows the file to be writable. Also, this method returns true if the operation is successful ... Read More

To check whether an element is in a HashSet or not in Java, use the contains() method.Create a HashSet −HashSet hs = new HashSet();Add elements to it −hs.add("R"); hs.add("S"); hs.add("T"); hs.add("V"); hs.add("W"); hs.add("Y"); hs.add("Z");To check for an element, for example, S here, use the contains() −hs.contains("S")The following is an example ... Read More

To get lower key means returning the greatest key strictly less than the given key. This can be done using lowerKey() method.The following is an example to get lower key from NavigableMap −Example Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { ... Read More

Getting ceiling key means to return the least key greater than or equal to the given key. For this, use the ceilingKey() method.The following is an example to get ceiling key from NavigableMap.Example Live Demoimport java.util.*; public class Demo { public static void main(String[] args) { ... Read More

To get enumeration over HashSet, first declare the HashSet and add elements −HashSet hs = new HashSet(); hs.add("P"); hs.add("Q"); hs.add("R");To get enumeration −Enumeration e = Collections.enumeration(hs);The following is an example to get Enumeration over HashSet −Example Live Demoimport java.util.*; public class Demo {    public static void main(String[] args) {   ... Read More

With Java, you can initialize a set without using add() method.For this create a string array −String arr[] = { "A", "B", "C", "D", "E"};Now, use Set and asList() method to initialize the above string array to our Set −Set s = new HashSet(Arrays.asList(arr));The following is an example to initialize ... Read More

The higher() method in NavigableSet returns the least element strictly greater than the given element i.e. 35 here −higher(35);The following is an example to implement the higher method in Java −Example Live Demoimport java.util.NavigableSet; import java.util.TreeSet; public class Demo { public static void main(String[] args) { ... Read More

Use the put() method to add elements to LinkedHashMap collection.First, let us create a LinkedHashMap −LinkedHashMap l = new LinkedHashMap();Now, add elements −l.put("1", "Jack"); l.put("2", "Tom"); l.put("3", "Jimmy"); l.put("4", "Morgan"); l.put("5", "Tim"); l.put("6", "Brad");The following is an example to add elements to LinkedHashMap collection −Example Live Demoimport java.util.LinkedHashMap; public class Demo ... Read More

To convert ArrayList to HashSet, firstly create an ArrayList −List l = new ArrayList();Add elements to the ArrayList −l.add("Accent"); l.add("Speech"); l.add("Diction"); l.add("Tone"); l.add("Pronunciation");Now convert the ArrayList to HashSet −Set s = new HashSet(l);The following is an example to convert an ArrayList to HashSet in Java.Example Live Demoimport java.util.ArrayList; import java.util.List; import ... Read More

To create NavigableMap from TreeMap. The following is the declaration −NavigableMap n = new TreeMap();Now, add some elements to the NavigableMap created above −n.put("A", 888); n.put("B", 999); n.put("C", 444); n.put("D", 555); n.put("E", 666); n.put("F", 888); n.put("G", 999); n.put("H", 444); n.put("I", 555); n.put("J", 666);The following is an example to create NavigableMap ... Read More