Gain insights into Java essentials, including programming paradigms, objects, data types, and algorithms. Delve into extensive exercises to prepare for a software development career.

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This course is your detailed guide to the fundamentals of the Java programming language. This course will get you on the fast track to becoming a proficient and modern Java developer.

In this course, you will start by covering different programming paradigms like object-oriented and procedural programming. You will then cover the fundamentals of programming in Java such as: objects and data types, variables, arrays, and conditional statements.

In the latter half of the course, you will cover iterative constructs, useful algorithms, and data structures. With over 100 problems, 11 quizzes, and 9 challenges, this course will get you prepared for a career in software development.

A Complete Guide to Java Programming


# Reference variables
Now, we can give a summary of a few key rules about variables. We have found three types of variables so far: 
1.  Reference variable
2. Local variable
3. Instance variable

The reference variables are directly related to the object scope. We have seen some problems and studied their nature through those problems. 

# Local variables

Local variables have some special characteristics. They are declared within a block, or method, or constructor. When the method is called, or the block is entered, these local variables are created and destroyed when we leave the block or if the call is returned from the method. We cannot access these variables outside this block of code. Furthermore, we have to initialize local variables.



Therefore, we need to remember a few key factors about local variables and eventually, we can compare its position with the object state or field, of which we have discussed earlier.
 

Just like objects store their fields in instance variables, a method stores its temporary states in local variables. The syntax for declaration is the same. We don’t use any `local` keywords for that. According to its location, we can assume whether the role of the variable is local or not. It is always between the opening and closing brackets of a method. Moreover, it is visible only inside the method.


# Instance variables
The specialty of instance variables is directly related to the classes and objects. We can declare it outside any block, method, or constructor; but it must be inside a class. It is not mandatory that we should initialize the instance variable. Its default value is `0`. Objects store their states inside the fields or variables and that value is unique to each instance or object. 



Learn about the different types of variables with the help of examples in this lesson.

Java, a High Level Language with a Purpose

How Java Programming Works

Objects and Data Types

Variables: The Name of a Field

Arrays: The Container Objects

Operators and Conditional Statements

Iterative Constructs, Entry and Exit Controlled Loops

Algorithms

Basic Input and Output

Classes and Objects

Interface and Abstraction

Exception Handling and Data Structures

Conclusion

Appendix

Types of Variables: Part 1