Tag: Java interview question
Java Set is a collection of elements (Or objects) that contains no duplicate elements. Java Set is an interface that extends Collection interface. Unlike List, Java Set is NOT an ordered collection, it’s elements does NOT have a particular order. Java Set does NOT provide a control over the position where you . . . Read more
Why do we have to override the equals() method in Java? We can use the equals method to check equality of two objects. The equals() method of java.lang.Object class acts the same as the == operator; that is, it tests for object identity rather than object equality. The implicit contract of the equals() method, however, is . . . Read more
What is the meaning of hashCode in Java? For every object a unique number generated by JVM which is nothing but hashCode. Hashcode won’t represent an address of the object. JVM will use hashCode while saving the object into hashing related data structures like HashTable, HashSet, HashSet, etc.. The main . . . Read more
What is Daemon thread and How to make Daemon thread? The threads which are executing in the background are called Demon threads. Ex… Garbage Collector, Signal Dispatcher, Attach Listener. The main objective of demon threads is to provide support for non-demon threads(main thread) For ex… If the main thread runs . . . Read more
What is synchronization and why it is important? Synchronized is the modifier applicable only for methods and blocks but not for classes and variables. If multiple threads are trying to operate simultaneously on the same java object then there may be a chance of data-inconsistency problem. To overcome this problem we should go . . . Read more
What is Transient Keyword in Java? Transient modifier applicable only for variables but not for methods and classes. We can use a transient keyword in serialization context. At the time of serialization if we don’t want to save a value of a particular variable to meet security constraint then we . . . Read more
Difference between normal import & static import? Explain import statement and difference between normal import & static import? To access a class or method from another package we need to use the fully qualified name or we can use import statements. The class or method should also be accessible. Accessibility . . . Read more
How many class can be public in Java Program? A JAVA Program can have any number no class but at most one class can be declared as public. If there is public class then the name of the Java program must be same as public class otherwise we will . . . Read more