Java Basic Concepts.

Since this days I’m spending lots of time doing programming in Java, I decided to make this page as a central repository of the more basic concepts in Java programming language that I will be updating over time.

Q: What is an object?

A: Objects are entities in your program that you manipulate by calling methods.

Q: What is a class?

A: A class defines the methods that you can apply to an object.

Q:What is a method?

A: A Java method is a set of Java statements which can be included inside a Java class.

Q: What is a constructor?

A: The process of creating a new object is called a construction.

Q: What is a variable?

A: A variable is a storage location in the computer’s memory that has a type, name, and content.

Q: What is a getter method?

A: A getter method whose purpose is to get the value of an instance or class value.

Q: What is a setter method?

A: A method whose purpose is to set the value of an instance or class value.

Q: What are some of the data types?

A: int, String, double, long, boolean.

Q: What is the main method of a Java program?

A: public static void main ( String [] args )

Q: what is Overloading?

A: Overloading is the ability to define more than one method with the same name in a class. When one of the methods is called the compiler uses their method signatures to be able to distinguish between them.

Q: What is an interface?

A: A Java interface declares a set of methods and their signatures.

Q: What is Polymorphism?

A: Polimorphism denotes the principle that behivors can vary depending on the actual type of an object.

Q: What is inheritance?

A: Inheritance is the ability to define a new class using an existing class as the basis.

Q: What is the difference between a superclass and a subclass?

A: The more genaral class is called SuperClass. The more specialized class that inherits from the superClass is called SubClass.

Q: What is toString method used for?

A: Define the toString method to yield a string that defines the object state

Q: What is cohesion?

A: Cohesive means that a certain class performs a set of closely related actions.

Q: What is an Accessor?

A: Methods that return variables. The accessor method name should start with “get”.

Q: What is a Mutator?

A: Methods that alter variables. The mutator method name should start with “set”.

Q: What is inheritance?

A: is the ability to define a new class using an existing class as the basis.

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