JavaGoal

The TreeMap class has various methods that are used to operate the data of TreeMap. We have already discussed how to create a TreeMap in java. Here we will see how to put, get, iterate, and remove the element from TreeMap. Here is the table content of the article will we will cover this topic.How … Read more

The HashMap and LinkedHashMap are the most widely used collection in java. Both are very popular to store the object based on key-value pairs. But both have some similarities and differences also. Here we will discuss the difference between HashMap and LinkedHashMap. So let’s find the HashMap vs LinkedHashMap. Difference between HashMap and LinkedHashMap 1. … Read more

We have learned about HashMap and ConcurrentHashMap in java. Both are the most popular concepts of Java. But HashMpa was introduced in JDK 1.2 and ConcurrentHashMap introduced in 1.5. So it is the most common question for an interview What is the difference between hashmap and Concurrenthashmap? and What is the need of Concurrenthashmap in … Read more

We have learned about HashMap in java and how does it work internally. As we have seen HashMap doesn’t support multithreading.  To support multithreaded environment to HashMap, Java provides ConcurrentHashMap in java that is part of the Concurrency Collection Classes. The ConcurrentHashMap is used in a multi-threaded environment to avoid ConcurrentModificationException. Here is the table content … Read more

Like other collections, we can’t directly traverse map in java. To iterate hashmap in java we can use the HashMap iterator() method and java map foreach() method. In this post, we will see how to Iterate a HashMap in Java. As we already know HashMap stores data in form of entry and each entry is … Read more

A HashMap stores all the objects in form of entries. An entry is a pair of key and value, Each value associated with a unique key. By using java entryset() method we can get all the entries from the HashMap. As we know we can’t directly transverse on HashMap, So it is one of the … Read more

As we know, A HashMap stores the data in form of key-value(Pair). Each pair is known as an entry in HashMap. HashMap stores all the value with its corresponding keys. We can get all the keys from HashMap by use of the keySet() method. This method returns all the keys as a Set. Let’s see … Read more

We have learned a lot of things about HashMap in java and the internal working of HashMap. Here we will learn how to check the given key is presented in HashMap or not. The hashmap containskey() method is used to check whether the map contains key or not? Let’s see the containskey() java. containsKey(Object key) … Read more

We have read how does put() method work and by using the put() method we can replace the existing object of HashMap. In this post, we will see another way to replace the object of Hashmap by use of java hashmap replace. Here is the table content of the article will we will cover this … Read more

We have learned, how to insert objects in HashMap and get the element from HashMap. In this post, we will learn how to remove object from HashMap by use of hashmap remove() method. We can remove the entry from the HashMap by value or key (java map remove by value or java hashmap remove). Here … Read more