How to use multiple classes in java

Can you have multiple classes in Java?

Yes you can have more than one class inside a . java file. … Having many classes inside one file means those classes are in the same package. So any other classes which are inside that package but not in that file can also use those classes.

How do you implement multiple classes in Java?

A Java class can only extend one parent class. Multiple inheritance ( extends ) is not allowed. Interfaces are not classes, however, and a class can implement more than one interface. The parent interfaces are declared in a comma-separated list, after the implements keyword.

How a Java program can include two or more classes and then combine them?

How the compiler behave with Multiple non-nested classes. In the below example, the java program contains two classes, one class name is Computer and another is Laptop. Both classes have their own constructors and a method. In the main method, we can create an object of two classes and call their methods.

How do you create different classes in Java?

To create an object of MyClass , specify the class name, followed by the object name, and use the keyword new :

  1. Example. Create an object called ” myObj ” and print the value of x: public class MyClass { int x = 5; public static void main(String[] args) { MyClass myObj = new MyClass(); System. …
  2. Example. …
  3. OtherClass.

Can we have multiple public class within a class?

As per java language specification, there can be only one public class in a file (. java) and file name should be same as public class name. If you want class B accessible in other placs, you may create a separate B.

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How many classes are there in Java?


How many classes can implement an interface?

A class can implement more than one interface at a time. A class can extend only one class, but implement many interfaces. An interface can extend another interface, in a similar way as a class can extend another class.

What is diamond problem in Java?

The “diamond problem” is an ambiguity that can arise as a consequence of allowing multiple inheritance. It is a serious problem for languages (like C++) that allow for multiple inheritance of state. In Java, however, multiple inheritance is not allowed for classes, only for interfaces, and these do not contain state.

How do you implement a class?

To declare a class that implements an interface, you include an implements clause in the class declaration. Your class can implement more than one interface, so the implements keyword is followed by a comma-separated list of the interfaces implemented by the class.

What is Java class $1?

java contains a top-level class (called WelcomeApplet ) and an anonymous inner class, which will be stored in WelcomeApplet$1. class . Note that the exact name of the files holding anonymous inner classes is not standardized and might vary.

What is the maximum number of classes can a Java program have?

If c is the number of valid character (we ignore that an Identifier may not begin with a digit in Java, and that Class names should begin with a capital letter), and d is the depth of the Package path we can have c^255 different Class names that can be qualified with c^255^d Packages.

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How many classes can be defined in a single program?

9. How many classes can be defined in a single program? Explanation: Any number of classes can be defined inside a program, provided that their names are different. In java, if public class is present then it must have the same name as that of file.

What is the difference between class and object?

A class is a template for objects. … A class also describes object behavior. An object is a member or an “instance” of a class. An object has a state in which all of its properties have values that you either explicitly define or that are defined by default settings.

What is void in Java?

The void keyword specifies that a method should not have a return value.

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