Table of Contents
How many types of packages are there?
There are two types of packages: User-defined and built-in packages. A package is Java’s style of bundling classes together. A package is a collection of related classes and interfaces. A package does not mean only predefined classes; a package may contain user defined classes also.
What are Java packages?
A package is a namespace that organizes a set of related classes and interfaces. The Java platform provides an enormous class library (a set of packages) suitable for use in your own applications. This library is known as the “Application Programming Interface”, or “API” for short.
What are the packages in JDK?
All Packages
| Package | Description |
|---|---|
| jdk.nio | Defines JDK-specific channel APIs. |
| jdk.security.jarsigner | This package defines APIs for signing jar files. |
| netscape.javascript | Provides Java code the ability to access the JavaScript engine and the HTML DOM in the web browser. |
Can we have two packages in Java?
Technically you can have a same class with same content in two different packages but then when you use these 2 classes in another Java class then you would have to be very specific (absolute package name) when using either of the class.
How do packages work in Java?
Creating a package in Java is a very easy task. Choose a name for the package and include a package command as the first statement in the Java source file. The java source file can contain the classes, interfaces, enumerations, and annotation types that you want to include in the package.
What means packaging?
Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging contains, protects, preserves, transports, informs, and sells.
How are packages created in Java?
To create a package, you choose a name for the package (naming conventions are discussed in the next section) and put a package statement with that name at the top of every source file that contains the types (classes, interfaces, enumerations, and annotation types) that you want to include in the package.
What is package structure in Java?
A Java package structure is like a directory structure. Its a tree of packages, subpackages and classes inside these classes. A Java package structure is indeed organized as directories on your hard drive, or as directories inside a zip file (JAR files).
What is import package in Java?
To import java package into a class, we need to use java import keyword which is used to access package and its classes into the java program. Use import to access built-in and user-defined packages into your java source file so that your class can refer to a class that is in another package by directly using its name.
What is package level access in Java?
package level access is the default access level provided by Java if no access modifier is specified. These access modifiers are used to restrict the accessibility of a class, method, or variable on which it applies.
How many packages and classes are there in Java?
The following are the count for number of packages and classes in java 6 / 7 / 8/ 9/ 10/ 11/ 12/ 13/ 14 . Hope this helps!!!. If you have some questions / doubts please comment.
What are the advantages of package in Java?
Advantage of Java Package 1 Java package is used to categorize the classes and interfaces so that they can be easily maintained. 2 Java package provides access protection. 3 Java package removes naming collision.
What are the built-in packages in Java?
There are many built-in packages such as java, lang, awt, javax, swing, net, io, util, sql etc. Here, we will have the detailed learning of creating and using user-defined packages.
How to access package from another package in Java?
How to access package from another package? 1 Using packagename.* If you use package.* then all the classes and interfaces of this package will be accessible but not subpackages. 2 Using packagename.classname If you import package.classname then only declared class of this package will be accessible. 3 Using fully qualified name