What is the difference between the public and default access specifiers?

Answer 1

Here is a brief explanation of the access modifiers allowed in Java: default: objects are visible from within their own class, or any other class in the same package. public: objects are visible from within their own class, or from any other class within the project (regardless of which package it is in). protected: objects are visible from within their own class or any other class within the same package; objects are also visible from any class that is a subclass. private: objects are only visible from within from within their own class. It is important to note that all but the default access modifier need to be specified. For example: public String foo; (public) protected String foo; (protected) private String foo; (private) String foo; (default) For more information on this topic, you can read this page: http://java.sun.com/docs/books/tutorial/java/javaOO/accesscontrol.html

Answer:

Public access modifier Fields, methods and constructors declared public (least restrictive) within a public class are visible to any class in the Java program, whether these classes are in the same package or in another package. public classes, methods, and fields can be accessed from everywhere. The only constraint is that a file with Java source code can only contain one public class whose name must also match with the filename. If it exists, this public class represents the application or the applet, in which case the public keyword is necessary to enable your Web browser or appletviewer to show the applet. You use public classes, methods, or fields only if you explicitly want to offer access to these entities and if this access cannot do any harm.

Default access modifier Java provides a default specifier which is used when no access modifier is present. Any class, field, method or constructor that has no declared access modifier is accessible only by classes in the same package. The default modifier is not used for fields and methods within an interface. If you do not set access to specific level, then such a class, method, or field will be accessible from inside the same package to which the class, method, or field belongs, but not from outside this package. This access-level is convenient if you are creating packages. For example, a geometry package that contains Square and Tiling classes, may be easier and cleaner to implement if the coordinates of the upper-left corner of a Square are directly available to the Tiling class but not outside the geometry package.

Answer 2

If you do not specify an access control modifier the compiler will use the default of whatever language you are using