How to Use Java’s Static Keyword

Danielle Ellis
Danielle Ellis

Published:

Are you looking to boost your programming prowess? You're in the right place. The static keyword is one of the most powerful features in Java, and mastering it is essential for creating scalable and efficient programs.

developer using the java static keyword in her work

Download Now: An Introduction to Java & JavaScript

But let's face it, even experienced developers can sometimes feel confused about the complexities of static behavior in code. Isolated instances, classes, and objects may all seem similar, but there are important differences to understand.

In this blog post, we'll dive deep into the world of Java's static keyword, discussing its implications and best practices. Whether you're a coding newbie or a seasoned developer, you'll leave with a solid understanding of using the static keyword to supercharge your programming workflow.

So, let's get started.

What is Static Java?

To use the static keyword in your code, you need to first understand exactly what it does. Let's break it down.

The static keyword indicates that a particular field, method, or block belongs to a class and not to an instance or object of that class. This means that any static field, method, or block is shared across all instances and objects of the class.

When using static, you must adhere to the syntax rules of Java. Here's an example of how to declare a static variable:

public class MyClass { public static int myStaticVariable; }

In the above example, the variable myStaticVariable is declared with the static keyword. Any other class can access this variable by referencing MyClass.myStaticVariable, without needing to create an instance of the class.

Let's say you had a Java class called "Car" with a static field called "wheels" that any instance of the "Car" class could use. All instances of the class will have access to the "wheels" field, regardless of whether or not they are instantiated with an explicit value.

When any instance of the "Car" class is created, it will still be able to see the static "wheels" field and access it just like any other field in the class.

In other words, the static keyword allows a class to have variables and methods that are shared across all instances.

How to Use the Static Keyword in Java

The static keyword is used to declare a static variable or method.

Static Variables

Static variables are defined with the "static" keyword and hold values that are shared among all instances of a class. These variables are created only once, at the start of the program, and can be accessed by all instances of the class. This can save memory and computation time by eliminating the need to create separate copies of the same variable for each instance of the class.

To illustrate this concept, let's consider an example where we have a class called "Person," and we want to keep track of the number of instances of that class created.

public class Person { // static variable to keep track of the number of instances created public static int count = 0; // constructor for Person class public Person() { count++; } }

In this example, the static variable "count" is incremented every time an instance of the Person class is created. This allows us to keep track of the total number of instances created without having to create a separate variable for each instance.

Static Methods

Static methods, like static variables, are defined with the "static" keyword and can be accessed without creating an instance of the class. This means that you can call the method directly on the class itself without having to create an object of the class first.

Static methods are often used for utility functions that don't require access to instance-specific data. For example, a static method might be used to convert a temperature from Celsius to Fahrenheit. Since this calculation doesn't require any instance-specific data, it can be performed by a static method that can be accessed without creating an instance of the class.

public class Temperature { // static method for conversion from Celsius to Fahrenheit public static double celsiusToFahrenheit(double celsius) { return (celsius * 9 / 5) + 32; } } double fahrenheit = Temperature.celsiusToFahrenheit(25); Output: 77.0

In this example, we've declared a static method in the Temperature class that can be used to convert a temperature from Celsius to Fahrenheit. It can be called directly on the class itself, without having to create an instance of the class first.

Static vs. Instance Methods in Java

In Java, methods are classified into two types: static methods and instance methods. While both types of methods serve different purposes, they are equally important in creating efficient Java programs.

As we have learned, static methods are defined using the "static" keyword and can be called without creating an object of the class. These methods are associated with the class itself, rather than any particular instance of the class, and can access only static variables. This makes them useful for performing operations that don't require access to instance-specific data, such as calculating a square root or converting a temperature.

On the other hand, instance methods are associated with a particular instance of a class and are called using an object of that class. They can access both static and instance variables and are useful for performing operations that require access to instance-specific data.

Let's take a look at the following example:

public class MyClass { private static int count = 0; private int id; public MyClass() { count++; id = count; } public static int getCount() { return count; } public int getId() { return id; } }

In this example, "count" is a static variable that is incremented every time an instance of the class is created. It can be accessed through the static method "getCount()," which returns the value of the static variable. The instance field "id" can only be accessed through an object of the class, using the instance method "getId()."

Best Practices for Using Java's Static Keyword

While the static keyword is a powerful tool in Java programming, there are a few best practices to keep in mind when using it in your code. By following these guidelines, you can ensure that your programs are efficient, maintainable, and easy to understand.

1. Limit the use of static variables

Static variables are shared across all class instances, making it difficult to keep track of their values and behavior. To avoid confusion and unexpected behavior, it's best to limit the use of static variables and use instance variables instead.

2. Use static methods for utility functions

Static methods are perfect for utility functions that don't require access to instance-specific data. By making a method static, you can call it without creating an object of the class, which can be more efficient and easier to understand.

3. Avoid using static methods for core functionality

While static methods are useful for utility functions, it's generally not a good idea to use them for core functionality. This is because static methods are difficult to override and can't be used to implement interfaces. Instead, use instance methods for core functionality and only use static methods when necessary.

4. Don't make methods static just to avoid creating objects

Creating objects in Java is relatively inexpensive, so there's no need to make methods static just to avoid creating objects. In fact, creating objects can actually be beneficial for readability and maintainability.

5. Use static imports sparingly

Static imports can make your code more concise, but they can also make it harder to read and understand. Use static imports sparingly and only for commonly used constants or methods.

Following these best practices, you can use the static keyword effectively and efficiently in your Java programs. Remember to use static variables and methods sparingly and only when necessary, and always keep maintainability and readability in mind.

New Call-to-action

Topics: Java

Related Articles

We're committed to your privacy. HubSpot uses the information you provide to us to contact you about our relevant content, products, and services. You may unsubscribe from these communications at any time. For more information, check out our Privacy Policy.

Learn more about one of the world's most popular programming languages.