In “How HashMap works in Java“, we learned the internals of HashMap or ConcurrentHashMap class and how they fit into the whole concept. But when the interviewer asks you about HashMap related concepts, he does not stop only on the core concept. The discussion usually goes in multiple d...
HashMap<String, String> map = new HashMap<>(); map.put("+1", "USA"); map.put("+91", "India"); map.get("+1"); // returns "USA" map.get("+2"); // returns null Note that HashMap is an unordered collection, and doesn’t guarantee the insertion order of key-value pairs...
4What is Collection API? The Collection API is a set of classes and interfaces that support operation on collections of objects. These classes and interfaces are more flexible, more powerful, and more regular than the vectors, arrays, and hashtables if effectively replaces. Collection ---Set ...
10) What happens if we add the same key with different values to a HashMap? The new value replaces the old one because HashMap doesn't allow duplicate keys. 11) What is the use of load factor? The load factor in collections such as HashMap determines when the table should be resized...
53. How does Hashmap work?HashMap is a part of the Java collection framework. It uses a technique called Hashing. It implements the map interface. It stores the data in the pair of Key and Value. HashMap contains an array of the nodes, and the node is represented as a class. It ...
160 . Can you briefly explain about the Map interface? 161 . What is difference between Map and sortedMap? 162 . What is a HashMap? 163 . What are the different methods in a Hash Map? 164 . What is a TreeMap? How is different from a HashMap? 165 . Can you give an example of...
Java提供了volatile关键字来保证可见性。 当一个共享变量被volatile修饰时,它会保证修改的值会立即被更新到主存,当有其他线程需要读取时,它会去内存中读取新值。 而普通的共享变量不能保证可见性,因为普通共享变量被修改之后,什么时候被写入主存是不确定的,当其他线程去读取时,此时内存中可能还是原来的旧值,因此无法...
HashMap , TreeMap 的区别6. SpringBoot 启动的过程 (不会)7. Spring 中对象注入可能存在的问题 Autowired 注入 默认以 Type 注入,接口如果有多个实现类的话需要用 name ,默认是根据变量名为类名去找要注入的具体类,也可以使用 Qualifier 注解指定具体要注入的类名8. MySQL 中的最左匹配问题 1轮面试:视频...
hashcode()returns the hashcode value as an Integer. Hashcode value is mostly used in hashing based collections like HashMap, HashSet, HashTable….etc. According to the official documentation, The general contract ofhashCode()is: Whenever it is invoked on the same object more than once during ...
HashMap,LinkedHashMap,ConcurrentHashMap What is the purpose of theExceptionclass in Java? TheExceptionclass is the base class for all exception types in Java. It represents an exceptional condition that has occurred during the execution of a program. ...