Narayana Tutorial

Explain with example to describe when to use abstract class and interface? Consider a scenario where all Cars will have 4 tyres and other features can be different. In this case any subclass of Car has to have 4 tyres. This is a case where abstract class will be used and a default implementation for […]

How can we call the garbage collector? Garbage collector is automatically invoked when the program is being run. It can be also called by calling gc() method of Runtime class or System class in Java  

Which algorithm is used by garbage collector   Garbage collector uses many algorithms but the most commonly used algorithm is mark and sweep.  

Which part of JVM will allocate the memory for a java program?   Class loader sub sytem of JVM will allocate the necessary memory needed by the Java program.  

Why java is suitable for internet?   Java is suitable for internet because of two main reasons. It is system independent and hence its programs can run on any type of computer system on internet. It eliminates a lot of security problems for data on internet.  

What is difference between abstract class and interface?   Abstract class may or may not be contain abstract methods but a class should be called as abstract when it contains at least one abstract method. It can also contain n numbers of concrete method. Interface can contain only abstract ( non implemented) methods. The abstract […]

What is the difference between static and instance methods? Instance method belongs to the instance of a class therefore it requires an instance before it can be invoked, whereas static method belongs to the class itself and not to any class instance so it doesn’t need an instance to be invoked. Instance methods use dynamic […]

What is difference between function and method?   A method is a function that is written in a class. We do not have functions in Java, instead we have methods. This means whenever a function is written in Java. It should be written inside the class only. But if we take C++, we can write […]