How to Use the Static Keyword in Java

Have you ever thought about why the static keyword is in the main function of a Java program?

How to Use the Static Keyword in Java

Java is an object-oriented language, which means that developers can use design patterns to plan classes and types of software. The static keyword shows which fields and methods are part of the class declaration.

The main function has the static keyword because the Java Virtual Machine (JVM) must be able to call it without having to create anything from the package.

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In this post, we’ll talk about the Java static keyword and how it helps manage memory and the lifecycle of fields, methods, and classes. We’ll talk about the Java SDK’s static members (fields and methods) and then show how to use the static keyword to make nested classes.

Java’s Static Methods vs. Instance Methods

By default, Java links the instance of the class to the fields and methods that are part of the class. Developers don’t have to make a copy of the class in order to use the static scope’s methods.

So, the static scope and the instance scope are two different things. When you make a new object, the instance scope is made and can access the instance fields. The static scope, on the other hand, can only access the static fields and methods.

Static is used in some design patterns, like the singleton pattern. In a singleton pattern, you tell the JVM that each type can have only one instance.

By default, fields and methods in a class are limited to a single instance. This means that the fields you make are tied to the life of the type’s instance.

By default, the values stored in the other variable are not changed by these instances. This is also known as scoping at the instance level. Static scope is the other way to limit what can be seen. You can also call static scope “class scope,” since the class name, not the instance name, is used to access the fields and methods.

The id field in the code above is not an instance member. Instead, it is a static member. You use the name of the class, “Person,” instead of the name of the instance or the variable you create to get to this field.

Once you changed the static field, the change was reflected in the type. When an instance tries to get a static member’s value, it gets it from the class. Each type of class does not keep its static members separate.

A quick recap:

The static members belong to the type, while the instance members are specific to the instance where they are created and assigned.

A static member can be accessed from both the type variable and the instance variable. An instance member can only be accessed from the instance variable.

You can get to a static field from a non-static or instance method, but you can’t get to instance fields and members from a static method.

Java’s Static Fields and Methods

Using the static keyword in Java, you can change how fields, methods, and classes behave over time. In the section above, you learned how to use the static keyword for fields. You can also use them to make methods in a class static.

The static modifier lets you get to the methods right from the name of the type.

A lot of classes in the Java API use methods that are always the same. For example, one of the best-known and most-used String.format methods is a static declaration that lets developers format the output.

In Java, you can also use an instance variable to call one of the static methods. Accessing the static methods from an instance is not helpful because static methods can’t access the instance fields and members. You can use the format method on String variables, but you have to give the value again (because the format method cannot access the instance value).

You can call the format method on the template variable, but the method can’t read the template value because that is in the instance scope, not the static or class scope. This becomes an anti-pattern because it makes the code and the called methods not match up. Because of this, it is always best to call the static methods on the type itself instead of the instance.

You can use the static keyword to create static blocks in addition to static fields and methods. This makes Java a much stronger language and lets developers make context whenever they need to.

But the Java static keyword can do more than just that. The next thing we’ll talk about is nested static classes, which are another interesting feature.

Java’s Constants and Classes Within Classes

Like C-like programming languages, Java doesn’t have a special keyword for defining constants. The last keyword in Java can be used to make a field read-only or assign-once. Using the constructor, you can set a final variable’s value when the program starts and keep it throughout the program’s life.

The static keyword makes sure that you only have to set up the member fields once and that they are used for the whole class.

Note that the word “static” means you don’t need to create an instance to get to the values. This method is used by a number of APIs. For instance, the Math library uses static keywords to show what PI, MAX VALUE, and other values are. The last keyword makes it assignable only once.

Static classes are another thing you can do with the static keyword. You can create classes inside of other classes and use the name of the parent class to get to them.

You should think about extending the Gamer type from the Person type instead of making nested classes if you want to use object-oriented development. But this depends on how you want to grow.

How to Use Java’s “Static” Keyword

You can use the Java static keyword in many ways when building websites, but one of the most common is in a Java program’s main function.

This tells the JVM how to start a static context. Since the main function is static, the JVM does not need to create an instance of the class that holds this method. But because of this, the main method can’t use instance fields or members made in the same class.

The singleton pattern is another place where you can use the static keyword. The singleton pattern makes sure that a program only makes one instance of a class. Things to remember about a singleton pattern are:

It’s a private builder.

It is a static method that lets the instance be accessed.

Hide the constructor in your type so that other types can’t make copies of it. Then, make a method that can be called even if there is no instance of this type. Since the method can get to the constructor, you make a new instance and give it back. Before you return, you save it in a static field of the type. The getInstance method and the instance field do not need an instance to be created. Outside types can use this method to get a hold of an instance and use it when they need it, but they can’t make an instance on their own.

Using the “static” word when programming in Java

In this article, you learned about the Java “static” keyword and how it can help you make your apps run faster and your code easier to understand. The article explained how static fields are different from default fields, which are also called instance fields. Then you learned how to make static fields and how to use them in Java programs. You can use the static keyword in field, method, and class declarations to control how they act during their lifetime.

Since Java doesn’t have a const keyword like other C-like programming languages, you should now have a better idea of how to use the static keyword to create constants. With the static keyword, you can change how long fields and variables in a Java program live.

When creating an instance of a type slows down the program, like when it’s used in an embedded device, the static keyword can be used to initialize the type throughout the life of the program. The static keyword lets you control how fields and variables use memory and how memory is managed in a Java program.

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