Frequent question: Can one Java file have two public classes?

Yes, it can. However, there can only be one public class per . java file, as public classes must have the same name as the source file. There can only be one public class top level class in a file.

Can I have multiple public classes in one Java file?

Long story short: no, you can’t put two public classes in one file because the compiler wouldn’t be able to handle that correctly.

Can we write 2 classes in a single Java file?

You can use at most one public class per one java file (COMPILATION UNIT) and unlimited number of separate package-private classes. … You also can have in your public class the unlimited number of inner classes and static nested classes .

Why can’t we have more than one public class in the same file?

There can be only one public class in a java file because the name of java file is same as the name of public class. And obviously we can’t have a file with two different names.

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How do I make two classes in one package?

7 Answers

  1. Rename Shapeclass to Shape … we know it’s a class already. Putting “class” in a class name adds no value.
  2. Since you require subclasses to declare an area() method, call that from within your print() method.
  3. Don’t store the area value in your shape – just call the area()` method if you need it.

Why we can not declare multiple public classes in single Java file?

So when we provide more than one public class in a program the compiler itself stops you by throwing an error. This is because later we can’t confuse the JVM as to which class is to be its initial class, because only one public class with the public static void main(String args[]) is the initial class for JVM.

How can we use two classes in java?

In general, Java has a main public class with a name that should match with the Java class file name and it calls other classes from this main class. The second approach is to write each class in different files and link them together with a package. In other words, all class files should be in the same class.

How many classes can be defined in a single java program?

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. 10.

Should Java classes be in separate files?

It is technically legal to have multiple Java top level classes in one file. However this is considered to be bad practice (in most cases), and some Java tools may not work if you do this. The JLS says this: When packages are stored in a file system (§7.2.

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How do you combine two classes in Java?

One Java file can consist of multiple classes with the restriction that only one of them can be public. As soon as you remove public keyword from your classes, you can combine them into a single Java file. “with the restriction that only one of them can be public”…

Why must a Java file have the same name as its public class?

The filename must have the same name as the public class name in that file, which is the way to tell the JVM that this is an entry point. … In this condition, we will not able to easily identify which class need to interpret by java interpreter and which class containing Entry point for the program.