A directory can be created with the required abstract path name using the method java.io.File.mkdir(). This method requires no parameters and it returns true on the success of the directory creation or false otherwise.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public class Demo {   ... Read More

Use the containsValue() method to check if a given value exists or not in a HashMap.First, let us create a HashMap and add some elements −HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new ... Read More

Use the remove() method to remove a value from TreeMap.Create a TreeMap first and add some elements −TreeMap m = new TreeMap(); m.put(1, "PHP"); m.put(2, "jQuery"); m.put(3, "JavaScript"); m.put(4, "Ruby"); m.put(5, "Java"); m.put(6, "AngularJS"); m.put(7, "ExpressJS");Now, let’s say you need to remove a value with key 5. For that, use ... Read More

In computer networking, pipelining is the method of sending multiple data units without waiting for an acknowledgment for the first frame sent. Pipelining ensures better utilization of network resources and also increases the speed of delivery, particularly in situations where a large number of data units make up a message ... Read More

First, create a HashMap and add elements to it −// Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Now, to modify the value associated with a given key, use ... Read More

A file or directory with the required abstract pathname can be deleted when the program ends i.e. after the virtual machine terminates using the method java.io.File.deleteOnExit(). This method requires no parameters and it does not return a value.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public ... Read More

Use the remove() method to remove a key only if it is associated with a given value.Let’s say the following is our HashMap −// Create a hash map HashMap hm = new HashMap(); // Put elements to the map hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800)); hm.put("Wallet", new ... Read More

Use the remove() method to remove a key from TreeMap.Let us first create a TreeMap and add some elements −TreeMap m = new TreeMap(); m.put(1, "India"); m.put(2, "US"); m.put(3, "Australia"); m.put(4, "Netherlands"); m.put(5, "Canada");Let us remove a key now. Here, we are removing key 3 now −m.remove(3)The following is an ... Read More

The attribute of a file can be changed to read-only by using the method java.io.File.setReadOnly(). This method requires no parameters and it returns true if the file is set to read-only and false otherwise.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public class Demo {   ... Read More

To copy, use the putAll() method.Let us first create two Map −First Map −HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600));Second Map −HashMap hm2 = new HashMap(); hm.put("Bag", new Integer(1100)); hm.put("Sunglasses", new Integer(2000)); hm.put("Frames", new Integer(800));Now, copy the key-value pairs from one Map to another −hm.putAll(hm2);The following ... Read More