CODEWITHSUNDEEP
java
ckersch
ckersch

Reputation: 7687

Are undeclared classes in Java public?

I'm starting to learn java and have created my first hello world function in Eclipse. I've noticed that the following two functions, both in the default package of the src folder in my java project, seem to do the same thing:

class HelloWorld {
    public static void main(String[] args){
        System.out.println("Hello World!");
    }
}

and

public class HelloWorld {
    public static void main(String[] args){
        System.out.println("Hello World!");
    }
}

Both successfully print 'Hello World!' to the console.

I've read a bit about different class types, but am unsure what type of class I would be declaring with the first function. What's the difference between these two functions? Does java make my hello world class in the first case public?

Upvotes: 5

Views: 2826

Answers (4)

Matyas
Matyas

Reputation: 13702

Class that is not declaring itself as public is package protected, meaning that the class it is only accessible in that package.

Very useful summary of acccess modifiers on stackoverflow. More at oracle

Example:

So let's say you have the following package structure:

com
  stackoverflow
    pkg1
      public Class1
      Class2
    pkg2
      OtherClass

Class2 can only be used by Class1, but not by OtherClass

Upvotes: 10

Matt Taylor
Matt Taylor

Reputation: 3408

This took me about 2 seconds to find on Google:

http://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html

In answer to your question, the default modifier is package protected, meaning it can only be accessed within the package, but next time please do some research before posting a question, as it took you more time to write the question that it would have to search

Upvotes: 1

Suresh Atta
Suresh Atta

Reputation: 121998

It is protected class ,you cannot access that class out side the package.

If you not specify anything its by default protected

Upvotes: 0

TheEwook
TheEwook

Reputation: 11117

It's all about class visibility!

A class may be declared with the modifier public, in which case that class is visible to all classes everywhere. If a class has no modifier (the default, also known as package-private), it is visible only within its own package

http://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html

Upvotes: 1

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