Differences between Java and Android

Android
Although Java is used
As a development tool
But in actual development, we found that
Yes
Some different places. The android SDK references most Java sdks, and a few of them are discarded by the android SDK, such as the interface section and Java. AWT.
In addition to Java. AWT. Font, package is discarded and cannot be used in Android development. Add a Java game
During the process of porting to the Android platform, the difference between the android SDK and the Java SDK is very important. The package referenced from the Java SDK In the android SDK is listed as follows, and the functions of these Java packages are briefly described:

Package	Description
Java. AWT. Font	Provides font-related classes and interfaces .
Java. Beans	Contains classes related to beans development, that is, based on the javabeanstm Architecture Components .
Java. Io	Provides system input and output through data streams, serialization, and file systems.
Java. Lang	Provides basic classes for Program Design Using the Java programming language.
Java. Math	Class used to execute any precision Integer algorithm (biginteger) and any precision decimal algorithm (bigdecimal.
Java.net	Provides classes for network applications.
Java. Nio	Defines the buffer as a data container and provides an overview of other NiO packages.
Java. Security	For security Framework Provides classes and interfaces.
Java. SQL	Access and process storage using javatm Programming Language APIS for data in a data source (usually a relational database) .
Java. Text	Provides classes and interfaces for processing text, dates, numbers, and messages in a way unrelated to natural language.
Java. util	Including Collection framework, legacy collection classes, and event models , Date and time facilities, internationalization and a variety of Utility Classes (string tag generator, random number generator, and Bit Array ).
Java extension package
Javax. crypto	Provides classes and interfaces for cryptographic (encryption) operations.
Javax. microedition. khronos. EGL Javax. microedition. khronos. opengles Java binding for the OpenGL ES (r) API
Javax.net	Provides classes for network applications.
Javax. Security. auth	This package is provided for identity authentication. And authorization framework.
Javax. Security. Auth. Callback	This package provides the classes necessary for interaction with the application to retrieve information (for example, authentication data including the user name and password) or display information (for example, error and warning messages ).
Javax. Security. Auth. Login	This package provides a pluggable authentication framework.
Javax. Security. Auth. x500	This package contains classes that should be used to store x500 principal and x500 private crendentials in subject.
Javax. Security. Cert	Is a Public Key Certificate Class.
Javax. SQL	Provides APIs for accessing and processing server-side data sources through the javatm programming language.
Javax. xml	Define Core XML constants and functions according to XML specifications.

The android SDK references the package of Java SDK 80%, which is frequently used in actual development. To learn more about data packets, click the link of each package.

The following shows some network-related packages in the android SDK.

Android SDK Network Package
Package	Description
Java.net	Provides networking-related classes, including streaming and data packet (datax) sockets, Internet protocols, and common HTTP processing. This package is a multi-function network resource. Experienced Java developers can immediately use this familiar package to create applications.
Java. Io	Although explicit networking is not provided, it is still very important. The classes in this package are used by sockets and connections provided by other Java packages. They are also used for interaction with local files that often occur when interacting with the network.
Java. Nio	Class that contains a buffer that represents a specific data type. It is suitable for communication between two Java-based endpoints.
Org. Apache .*	Indicates many packages that provide precise control and functions for HTTP Communication. Apache can be regarded as a popular open source Web server.
Android.net	In addition to the core java.net. * class, it contains additional network access sockets. This package includes the URI class, which is frequently used for Android application development, not just traditional networking.
Android.net. HTTP	Contains classes for processing SSL certificates.
Android.net. WiFi	Includes classes for managing all aspects of wifi (802.11 Wireless Ethernet) on the Android platform. Not all devices are equipped with WiFi functions, especially for Android phones such as Motorola and LG. The provider's "flip phone" field was successful.
Android. telephony. GSM	Contains classes used to manage and send SMS (text) messages. After a period of time, additional packages may be introduced to provide similar functions for non-GSM networks, such as CDMA or android. telephony. CDMA.