java 13 interview questions and answers

Vector implements a dynamic array. It is similar to ArrayList, but with two differences:  Vector is synchronized, and it contains many legacy methods that are not part of the collections framework. In Core Java, a “vector” typically refers to the Vector class, which is a part of the Java Collections Framework. The Vector class implements a dynamic array that … Read more

Hashtableis synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones. Hashtabledoes not allow null keys or values. HashMap allows one null key and any number of null values. One of HashMap’s subclasses is LinkedHashMap, so in the event that you’d want predictable iteration order (which is insertion order by default), you could … Read more

Map is Interface and Hashmap is class that implements that In Java, Map is an interface that represents a collection of key-value pairs, where each key is associated with exactly one value. HashMap is a specific implementation of the Map interface. Here are some key differences between Map and HashMap: Interface vs. Implementation: Map is the interface … Read more

Map is an object that maps keys to values. A map cannot contain duplicate keys: Each key can map to at most one value. This Map permits null value In Java, the Map interface is a part of the Java Collections Framework and is used to represent a collection of key-value pairs where each key must be … Read more

Java Collections Framework provides a set of interfaces and classes that support operations on a collections of objects. The Java Collections API is a set of classes and interfaces in Java that provide a framework for working with collections of objects. A collection is an object that represents a group of objects, known as elements. … Read more