import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class CountDuplicatedItemInList { public static void main(String[] args) { List<String> list = new ArrayList<String>(); list.add("a"); list.add("a"); list.add("b"); list.add("b"); list.add("c"); list.add("c"); Map<String,…
In Java, you can use map's contains method to check if a key exists in map or not. import java.util.HashMap; import java.util.Map; public class HashMapCheckIfKeyExists { public static void main(String[]…
This post will show you how to use Java & Groovy together to build a Restful API. Make sure you have already installed the Groovy Library. If not, you can…
Java syntax is defined in the Java language specification, and the Java library is defined in the Java application program interface (API). The JDK is the software for compiling and…
Often, it is desirable to create a copy of an object. To do this, you need to use the clone method and understand the Cloneable interface. An interface contains constants…
A class can implement multiple interfaces, but it can only extend one superclass. An interface can be used more or less the same way as an abstract class, but defining…
You have to create your program and compile it before it can be executed. This process is repetitive, as this picture shows you. If your program has compile errors, you…
Runtime errors occur while a program is running if the JVM detects an operation that is impossible to carry out. For example, if you access an array using an index…
You can implement a bucket using an array, ArrayList, or LinkedList. We will use LinkedList for demonstration. You can view each cell in the hash table as the reference to…
A collision occurs when two keys are mapped to the same index in a hash table. Gener- ally, there are two ways for handling collisions: open addressing and separate chaining.…