Yes, it can. However, there can only beone public class per . java file, as publicclasses must have the same name as the source file. OneJava file can consist of multiple classes withthe restriction that only one of them can bepublic..
Herein, 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).
Likewise, why should there be only one public class in Java? Compiler also puts the restriction that thereshould be atmost one public class per Java file,so that every public class can be accessed by the outsideworld. Any two Java classes or interfaces in the samepackage cannot have the same name.
One may also ask, why can't we have more than one public class in the same file?
So when we provide more than one publicclass in a program the compiler itself stops you bythrowing an error. This is because later we can'tconfuse the JVM as to which class is to be itsinitial class, because only one public class with thepublic static void main(String args[]) is the initialclass for JVM.
Can we create multiple classes in one Java?
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.
Related Question Answers
Can a class can be declared protected?
Since there's no such concept as 'subpackage' or'package-inheritance' in Java, declaring class protected orpackage-private would be the same thing. You can declarenested and inner classes as protected or private,though.Can final static method be overloaded?
Static methods cannot be overriddenbecause they are not dispatched on the object instance at runtime.The compiler decides which method gets called. Staticmethods can be overloaded (meaning that you canhave the same method name for several methods as longas they have different parameter types).Can we execute a class without a main method?
Yes You can compile and execute without mainmethod By using static block. But after static blockexecuted (printed) you will get an error saying nomain method found. And Latest INFO --> YOU cantDo this with JAVA 7 version. IT will notexecute.What is a source file in Java?
A Java source file is a plain text filecontaining Java source code and having .javaextension. The .java extension means that the file isthe Java source file. If there is a public class in afile, the name of the file must match the name of thepublic class.What is Java inheritance?
Inheritance is a mechanism wherein a new class isderived from an existing class. In Java, classes mayinherit or acquire the properties and methods of otherclasses. A class derived from another class is called a subclass,whereas the class from which a subclass is derived is called asuperclass.What is abstract class in Java?
An abstract class, in the context of Java,is a superclass that cannot be instantiated and is used to state ordefine general characteristics. An object cannot be formed from aJava abstract class; trying to instantiate an abstractclass only produces a compiler error.What is a constructor in Java?
Constructor is a block of code that initializesthe newly created object. A constructor resembles aninstance method in java but it's not a method as it doesn'thave a return type. Constructor has same name as the classand looks like this in a java code.How many classes can be defined in a single program?
9. How many classes can be defined in a singleprogram? Explanation: Any number of classes can bedefined inside a program, provided that their names aredifferent. In java, if public class is present then it musthave the same name as that of file.Does every class have a main method?
Without a main method you application willhave no entry point. Yes, it is required for any executableprogram. If you try to execute a Java class, the JVM willlook for a main method to invoke it. Not all classes needa main , only the one that serve as "entry point" forexecution.Which package is imported by default in Java?
The Java standard libraries includejava.lang package by default, which contains anumber of components that are used very commonly in Javaprograms. Java is useless without much of the functionalityin java.lang , that's why java.lang is implicitlyimported by the compiler for all programs.Is string a primitive data type in Java?
String is an object, in android or java itisn't a primitive type at all. you can use strings tostore in SharedPreferences. Strings are objects of theString class (java.lang.String). This is why aString is not a primitive data type, it is instead amyriad of attributes (int length, char[position],etc.).Why do we write public class in Java?
public is a Java keyword which declares amember's access as public. Public members arevisible to all other classes. This means that any otherclass can access a public field or method. Further,other classes can modify public fields unless thefield is declared as final . 
