6 : What is the difference between static and not static variable?
Answer : Main differences are as bellow.
- Static variables are preceded by static keyword. For non-static variable, there is not any preceding keyword.
- Memory is allocated for static variables at the time of class loading. Memory is allocated to non- static variables whenever an object is created.
- Memory is allocated only once to static variables on class loading. Memory is allocated multiple time whenever a new object is created to non-static variables.
- Static variable example : Collage name of students, Company name of employees..
READ MORE about static and non-static stuff.
7 : What is the difference between static and not static(Instance) method?
Answer : Difference between static and non static method is as bellow.
- Method declared with static keyword is static method. If Method declared without static keyword then it is instance method.
- No need of object to call static methods. Object needed to call instance method.
- Can not access non static stuff inside static methods directly. Opposite to it, We can access static and non static stuff directly inside instance method.
8 : What is inheritance in java?
Answer : In Java, Inheritance provides mechanism using which one object of child class can acquire all the properties and behaviors of parent object. It will crate IS-A relationship. Main usage of inheritance in java is for code re-usability and method overriding to achieve run-time polymorphism. VIEW MORE detail on inheritance.
9 : Multiple inheritance is supported in java on class level? If No.. Why?
Answer : No.. Multiple inheritance is not supported in java in case of class to simplify the language and reduce the complexity.
10 : What is method overriding in java?
Answer : Method overriding is a feature which allows a child class or sub class to provide a specific implementation of a method which is already provided by one of its parent classes or super class. It is used for runtime polymorphism. You can read more about method overriding on THIS POST.