How to Call a Method in Java

When starting to program with Java, there are many concepts that you need to grasp. Those concepts include class, method, exception, constructor, variable, and so on. In order not to be overwhelmed, it is best to learn little by little. This wikiHow teaches you how to call a method in Java.

Table of Contents

Steps

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You need to understand what a method is. In Java, a method is a set of commands grouped together to perform an action. After a method is declared, we can call different parts of the code to execute the function. This is a practical way to use the same code more than once. The following is an example of a simple method.

 public static void methodName () { System . out . println ( "This is a method" ); }

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Declare the access modifier of the method. When declaring methods in Java, you need to declare which classes can access the method. In the above example, accessibility is declared as “Public”. There are three possibilities you can declare for a method:

Public: By putting the “public” access modifier in front of the method name, we can call this method from anywhere.
Protected: The “protected” access allows the method to be called only in the scope of the base and subclasses.
Private: If access is declared private , the method can only be called from within the class. This access is called default or plan private. This means that only classes in the same package can call this method.

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Declare the class to which the method belongs. In the above example, the second keyword is “static”, which means that the method belongs to the class and not any instance or object of the class. The static method must be called by the class name: “ExampleClass.methodExample()”.

If the “static” keyword is not used, the method can only be called through an object. For example, if the class “ExampleObject” has a constructor (used to create an object), we can create a new object by typing “ExampleObject obj = new ExampleObject();”, and call the method with the following command. : “obj.methodExample();”.

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Declare the return value. Return value declares the name of the value returned by the method. In the above example, the word “void” indicates that the method returns no value.

If you want a method to return something, just replace the word “void<” with the data type (primitive or reference) of the object or primitive type you want to return. Primitive data types include int , float , double , and so on. Then add “return” along with the object of that data type at the end of the method’s code.
When calling a method that returns a certain value, you can continue to use that value. For example, if the “someMethod()” method returns an integer, you can set that integer to the value returned by code: “int a = someMethod();”

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Declare the method name. After you have declared the classes that have access to the method, the class to which the method belongs, and the return value, you need to give it a name so that the method can be called. To name a method, simply enter the method name along with opening and closing parentheses, such as “someMethod()” or “methodName()”. Then, type all the method commands inside the opening and closing curly braces “{}”

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Call method. To call a method, simply enter the method name along with opening and closing parentheses in the line you want to implement. Note: only call the method in the class that has access. The following is an example of a method declared and called in the class: ^{[1] X Research Source} .

 public class className { public static void methodName (){ System . out . println ( "This is a method" ); } public static void main ( String [] args ) { methodName (); } }

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Add parameters to the method (if necessary). Some methods need a parameter (such as an integer) or a reference type (for example, an object name). If a method requires a parameter, simply enter the parameter between the opening and closing parentheses after the method name. Here’s an example of a method that requires an integer parameter: “someMethod(int a)” or similar. Methods using a reference type will be of the form: “someMethod(Object obj)” or similar.

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Call a method that contains parameters. When calling a method that contains parameters, you just need to add the parameter in parentheses after the method name. For example, “someMethod(5)” or “someMethod(n)” where “n” is an integer. If the method requires an object reference, enter the object name within the opening and closing parentheses. Such as: “someMethod(4, thing)”.

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Add multiple parameters to a method. Methods can also contain multiple parameters, you just need to separate them with commas. Following is an example of a method created to add two integers together and return the sum as the return method. When this method is called, the two integers given as parameters add up. After the program executes, you will get output saying “The sum of A and B is 50”.:

 public class myClass { public static void sum ( int a , int b ){ int c = a + b ; System . out . println ( "The sum of A and B is " + c ); } public static void main ( String [] args ) { sum ( 20 , 30 ); } }

Advice

After calling a method and having a return value, you can call another method based on the value just returned. For example, if getObject() method returns an object, that means in the Object class there is a non-static method toString with the value Object returns when String is called. So if you want to get this String value from Object returned by getObject() in one line, write ” String str = getObject().toString(); “.

Warning

Note about abstract classes and methods. An abstract method cannot be used until it is implemented by another class. This is because the abstract method has no implementation code. Abstract classes are used as a kind of framework.

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Advice

Warning

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