Top Core Java Interview Questions :: ALLInterview.com http://www.allinterview.com Top Core Java Interview Questions en-us explain System.out.println http://www.allinterview.com/showanswers/23154.html System: System refers to current java program. out: out refers to output device. by default it is monitor. println: to print the specific string onto output device in next line explain oops concepts with examples? http://www.allinterview.com/showanswers/32553.html There are three types of oops in java. 1.Encapsulation:Encapsulation is mechanism,that binds together data and code its manipulates. Ex:suppose we are writing one bean.we declaring two private variables.we are providing setters and getters method what is the Diff. between Access Specifiers and Access Modifiers? http://www.allinterview.com/showanswers/1065.html Access specifiers :: The access specifier determines how accessible the field is to code in other classes. Access ranges from totally accessible to totally inaccessible. You can optionally declare a field with an access specifier keyword: p what is the difference between abstract class and Interface?where we http://www.allinterview.com/showanswers/11031.html 1)We define an Interface in the Java application with a set of abstract methods without any implementation. Which means all the methods of an interface are by default abstract methods and public methods. 2)Once an Interface is defined in the what is difference Between Core Java and advance java http://www.allinterview.com/showanswers/23767.html See the diffrence is that core java is the fundamental for java that will be used in any java technology without this no one can jump on any advance java technology. Where as advance java is specialisation in some domain , as someone in networki what is the difference between ArrayList and Vector http://www.allinterview.com/showanswers/20264.html 1. Arraylist is not synchronized while vector is. 2. Arraylist has no default size while vector has a default size of 10. why java does not support multiple inheritance http://www.allinterview.com/showanswers/16522.html Java absolutly support multiple inheritence in terms of Interface.We can extend one class only to avoid ambiguity problem.In interface we have to define the functions.So we don't get any ambiguity.In c++ it is big problem with multiple i what is the difference between HashMap and Hashtable http://www.allinterview.com/showanswers/20263.html Hashmap work as like as Hashtable but hashtable is synchronised hash map was not sychronized hashtable does not allow null values hashmap allows null values Difference between array and arraylist. http://www.allinterview.com/showanswers/4105.html A java.util.ArrayList has the following characteristics over an array: 1. Provides a resizable array implementation 2. Implements the java.util.List interface 3. Has a tuning parameter called initialCapacity which specifies the number of eleme what do you meant by Runtime Polymorphism? http://www.allinterview.com/showanswers/4100.html polymorphism -an entity existing in different forms at the same time. Polymorphism is of two types. Static polymorphism and dynamic polymorphism. Run time polymorphism refers to dynamic polymorphism wherein an entity changes it's form de what is the difference between static block and static method http://www.allinterview.com/showanswers/29134.html static block will execute when ever execution starts, it means this block executes first of all, where as static block have to call seperately and also it can call with out object instance. what is meant by string pooling? http://www.allinterview.com/showanswers/4967.html A string pool is a collection of references to String objects. Strings, even though they are immutable, are still objects like any other in Java. Objects are created on the heap and Strings are no exception. So, Strings that are part of the " Which is the best way to use for String concatenation in Java? http://www.allinterview.com/showanswers/6878.html Java provides the StringBuffer and String classes, and the String class is used to manipulate character strings that cannot be changed. Simply stated, objects of type String are read only and immutable. The StringBuffer class is used to represent What is a void return type? http://www.allinterview.com/showanswers/1989.html it states that the method doesn't return anything. what are the oops concept in java explain with real time examples http://www.allinterview.com/showanswers/59459.html Encapsulation Abstraction polymorphisms inheritance/delegation