Yes, it can. However, there can only beone public class per . java file, as publicclasses must have the same name as the sourcefile. One Java file can consist of multipleclasses with the restriction that only one of themcan be public.

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In this regard, can we have multiple public class within a class?

You can have multiple classes within a class.They are called Inner Classes or nested classes.You can even have multiple class definitionsin a single .java file without one being nested inanother (provided that only one is public, because apublic class has to be declared in a file named afterit).

Beside above, can a class contain another class in Java? In Java, just like methods, variables of aclass too can have another class as itsmember. Writing a class within another is allowed inJava. The class written within is called the nestedclass, and the class that holds the innerclass is called the outer class.

Likewise, people ask, can we have more than one package statement in source file?

There can be only one package statement ineach source file, and it applies to all types in thefile. Note: If you put multiple types ina single source file, only one can be public ,and it must have the same name as the source file.Otherwise, classes and interfaces belong in namedpackages.

Can you save Java source file without any name?

Yes,it is possible to compile a java source filewith different file name but you need to make surenone of the classes defined inside are publicwhen youcompile the source file the corresponding .classfiles for the classes inside the source file arecreated.

Related Question Answers

Can a class be static?

So, Yes, you can declare a class static inJava, provided the class is inside a top level class.Such classes are also known as nested classes andthey can be declared static, but if you are thinkingto make a top level class static in Java, then it's notallowed.

What are class access modifiers?

Access modifiers (or access specifiers)are keywords in object-oriented languages that set theaccessibility of classes, methods, and other members.Access modifiers are a specific part of programming languagesyntax used to facilitate the encapsulation of components. Aclass cannot be declared as private.

Can inner class extend any class?

Inner class can extend it's outer class.But, it does not serve any meaning. Even though, Whenan inner class extends its outer class, only fieldsand methods are inherited but not inner classitself.

Can a class have more than one main method in Java?

'main' means public static voidmain(String[] args) which is entry point in javaprograms . You can have more classes that contain themain() in a program . And you can choose to executeone class or another class. But you can'thave more than one main method (String[] args as arguments)within same class.

Can a class be private?

We can declare an inner class asprivate but we can not declare an outer classas private. As we know a field defined in a classusing private keyword can only be accessible withinthe same class and is not visible to the outsideworld.

Can inner class have constructor?

So the main class has to exist, and itsconstructor it is called first. Then the constructorsof the nested classes. otherwise it will not eveninvoke inner class constructor as it is not instantiated,like static blocks are executed, but instance blocks andconstructors are not invoked until you create anobject.

What is a singleton class in Java?

Singleton Class in Java. In object-orientedprogramming, a singleton class is a class that canhave only one object (an instance of the class) at a time.To design a singleton class: Make constructor as private.Write a static method that has return type object of thissingleton class.

How many inner classes can a class have?

Inner class means one class which is amember of another class. There are basically four types ofinner classes in java. Nested Inner class can accessany private instance variable of outer class. Like any otherinstance variable, we can have access modifier private,protected, public and default modifier.

Why main method is static?

Java program's main method has to be declaredstatic because keyword static allows main tobe called without creating an object of the class in which themain method is defined. If we omit static keywordbefore main Java program will successfully compile but itwon't execute.

Can I import same package class twice?

Will the JVM load the package twice atruntime? Answer: One can import the same package orsame class multiple times. Neither compiler nor JVMcomplains about it. And the JVM will internally load theclass only once no matter how many times you importthe same class.

What is a package give an example?

A package means a complete version of anapplication software installed on your computer, phone etc. Forexample, The MS Office package consists of Word,PowerPoint, Excel, Access, Publisher etc. The Adobe packageconsists of photoshop, flash etc.

What is Polymorphism in Java?

Polymorphism is the ability of an object to takeon many forms. The most common use of polymorphism in OOPoccurs when a parent class reference is used to refer to a childclass object. Any Java object that can pass more than oneIS-A test is considered to be polymorphic.

What is user defined package?

A package is a mechanism to group the similartype of classes, interfaces and sub-packages and provideaccess control. It organizes classes into single unit.

What is API in Java?

Java application programming interface(API) is a list of all classes that are part of theJava development kit (JDK). It includes all Javapackages, classes, and interfaces, along with their methods,fields, and constructors. These prewritten classes provide atremendous amount of functionality to a programmer.

What is class path in Java?

Classpath is a parameter in the JavaVirtual Machine or the Java compiler that specifies thelocation of user-defined classes and packages. The parametermay be set either on the command-line, or through an environmentvariable.

How many packages are there in Java?

We have two types of packages in Java:built-in packages and the packages we can create(also known as user defined package). In this guide we willlearn what are packages, what are user-definedpackages in java and how to use them. → andScanner is a class which is present in the sub packageutil.

Why is String final in Java?

Why String is Immutable or Final in Java.The string is Immutable in Java because Stringobjects are cached in String pool. At the same time,String was made final so that no one can compromiseinvariant of String class e.g. Immutability, Caching,hashcode calculation etc by extending and overridingbehaviors.

Can we create object of inner class in Java?

Any non-static nested class is known as innerclass in java. The object of java inner class arepart of the outer class object and to create aninstance of the inner class, we first need tocreate an instance of outerclass.

What are different types of inner classes?

There are four types of inner classes: member, staticmember, local, and anonymous.

• A member class is defined at the top level of the class.
• A static member class is defined like a member class, but withthe keyword static.
• A local inner class is defined within a method, and the usualscope rules apply to it.