What language is java?

Java language

Java language is an object-oriented programming language that supports network computing. Java language absorbs the advantages of Smalltalk language and C language, and adds other features, such as supporting concurrent programming, network communication, and multimedia data control. The main features are as follows:

1. The Java language is simple. The syntax of Java language is very close to C language and C language, making it easy for most programmers to learn and use Java. On the other hand, Java discards those features of C that are rarely used, difficult to understand, and confusing, such as operator overloading, multiple inheritance, and automatic casts. In particular, the Java language does not use pointers and provides automatic garbage collection so that programmers do not have to worry about memory management.

2. The Java language is object-oriented. The Java language provides primitives such as classes, interfaces and inheritance. For the sake of simplicity, it only supports single inheritance between classes, but supports multiple inheritance between interfaces, and supports the implementation mechanism between classes and interfaces (the keyword is implements) . The Java language fully supports dynamic binding, while the C language only uses dynamic binding for virtual functions. In short, the Java language is a pure object-oriented programming language.

3. The Java language is distributed. The Java language supports the development of Internet applications. Among the basic Java application programming interfaces, there is a network application programming interface (java.net), which provides class libraries for network application programming, including URL, URLConnection, Socket, ServerSocket, etc. Java's RMI (remote method activation) mechanism is also an important means of developing distributed applications.

4. The Java language is robust. Java's strong typing mechanism, exception handling, automatic collection of waste, etc. are important guarantees for the robustness of Java programs. Discarding pointers is a smart choice for Java. Java's security checking mechanism makes Java more robust.

5. The Java language is safe. Java is usually used in network environments. For this reason, Java provides a security mechanism to prevent malicious code attacks. In addition to the many security features of the Java language, Java has a security prevention mechanism (class ClassLoader) for classes downloaded through the network, such as allocating different name spaces to prevent replacement of local classes of the same name, byte code inspection, and providing security management Mechanism (class SecurityManager) allows Java applications to set up security sentries.

6. The Java language is architecture-neutral. Java programs (files with the suffix java) are compiled into an architecture-neutral bytecode format (files with the suffix class) on the Java platform, and can then be run on any system that implements this Java platform. This approach is suitable for heterogeneous network environments and software distribution.

7. The Java language is portable. This portability comes from architecture neutrality. In addition, Java also strictly regulates the length of each basic data type. The Java system itself is also highly portable. The Java compiler is implemented in Java, and the Java running environment is implemented in ANSI C.

8. The Java language is interpreted. As mentioned before, Java programs are compiled into bytecode format on the Java platform and can then be run on any system that implements this Java platform. At runtime, the Java interpreter in the Java platform interprets and executes these bytecodes, and the classes required during the execution are loaded into the running environment during the connection phase.

9. Java is high-performance. Compared with those interpreted high-level scripting languages, Java is indeed high-performance. In fact, the running speed of Java is getting closer and closer to C with the development of JIT (Just-In-Time) compiler technology.

10. The Java language is multi-threaded. In the Java language, a thread is a special object that must be created by the Thread class or its descendants (grandchildren).

There are usually two ways to create a thread: first, use the constructor of type Thread(Runnable) to wrap an object that implements the Runnable interface into a thread; second, derive a subclass from the Thread class and override run Method, the object created using this subclass is a thread. It is worth noting that the Thread class has implemented the Runnable interface, so any thread has its run method, and the run method contains the code to be run by the thread. The activity of a thread is controlled by a set of methods. The Java language supports the simultaneous execution of multiple threads and provides a synchronization mechanism between multiple threads (the keyword is synchronized).

11. The Java language is dynamic. One of the design goals of the Java language is to adapt to dynamically changing environments. The classes required by Java programs can be dynamically loaded into the running environment, and the required classes can also be loaded through the network. This also facilitates software upgrades. In addition, classes in Java have a run-time representation and can perform run-time type checking.

The excellent characteristics of the Java language make Java applications extremely robust and reliable, which also reduces the maintenance costs of the application system. Java's comprehensive support for object technology and the API embedded in the Java platform can shorten application system development time and reduce costs. Java's compile-once-run-anywhere nature enables it to provide an open architecture that can be used anywhere and a low-cost way to transfer information between multiple platforms. In particular, Java Enterprise Application Programming Interfaces (Java Enterprise APIs) provide relevant technologies and rich class libraries for enterprise computing and e-commerce application systems. Java language

Java language is an object-oriented programming language that supports network computing. Java language absorbs the advantages of Smalltalk language and C language, and adds other features, such as supporting concurrent programming, network communication, and multimedia data control. The main features are as follows:

1. The Java language is simple. The syntax of Java language is very close to C language and C language, making it easy for most programmers to learn and use Java. On the other hand, Java discards those features of C that are rarely used, difficult to understand, and confusing, such as operator overloading, multiple inheritance, and automatic casts. In particular, the Java language does not use pointers and provides automatic garbage collection so that programmers do not have to worry about memory management.

2. The Java language is object-oriented. The Java language provides primitives such as classes, interfaces and inheritance. For the sake of simplicity, it only supports single inheritance between classes, but supports multiple inheritance between interfaces, and supports the implementation mechanism between classes and interfaces (the keyword is implements) . The Java language fully supports dynamic binding, while the C language only uses dynamic binding for virtual functions. In short, the Java language is a pure object-oriented programming language.

3. The Java language is distributed. The Java language supports the development of Internet applications. Among the basic Java application programming interfaces, there is a network application programming interface (java.net), which provides class libraries for network application programming, including URL, URLConnection, Socket, ServerSocket, etc. Java's RMI (remote method activation) mechanism is also an important means of developing distributed applications.

4. The Java language is robust. Java's strong typing mechanism, exception handling, automatic collection of waste, etc. are important guarantees for the robustness of Java programs. Discarding pointers is a smart choice for Java. Java's security checking mechanism makes Java more robust.

5. The Java language is safe. Java is usually used in network environments. For this reason, Java provides a security mechanism to prevent malicious code attacks. In addition to the many security features of the Java language, Java has a security prevention mechanism (class ClassLoader) for classes downloaded through the network, such as allocating different name spaces to prevent replacement of local classes with the same name, byte code inspection, and providing security management Mechanism (class SecurityManager) allows Java applications to set up security sentries.

6. The Java language is architecture-neutral. Java programs (files with the suffix java) are compiled into an architecture-neutral bytecode format (files with the suffix class) on the Java platform, and can then be run on any system that implements this Java platform. This approach is suitable for heterogeneous network environments and software distribution.

7. The Java language is portable. This portability comes from architecture neutrality. In addition, Java also strictly regulates the length of each basic data type. The Java system itself is also highly portable. The Java compiler is implemented in Java, and the Java running environment is implemented in ANSI C.

8. The Java language is interpreted. As mentioned before, Java programs are compiled into bytecode format on the Java platform and can then be run on any system that implements this Java platform. At runtime, the Java interpreter in the Java platform interprets and executes these bytecodes, and the classes required during the execution are loaded into the running environment during the connection phase.

9. Java is high-performance. Compared with those interpreted high-level scripting languages, Java is indeed high-performance. In fact, the running speed of Java is getting closer and closer to C with the development of JIT (Just-In-Time) compiler technology.

10. The Java language is multi-threaded. In the Java language, a thread is a special object that must be created by the Thread class or its descendants (grandchildren). There are usually two ways to create a thread: first, use the constructor of type Thread(Runnable) to wrap an object that implements the Runnable interface into a thread; second, derive a subclass from the Thread class and override run Method, the object created using this subclass is a thread. It is worth noting that the Thread class has implemented the Runnable interface, so any thread has its run method, and the run method contains the code to be run by the thread. The activity of a thread is controlled by a set of methods. The Java language supports the simultaneous execution of multiple threads and provides a synchronization mechanism between multiple threads (the keyword is synchronized).

11. The Java language is dynamic. One of the design goals of the Java language is to adapt to dynamically changing environments. The classes required by Java programs can be dynamically loaded into the running environment, and the required classes can also be loaded through the network. This also facilitates software upgrades. In addition, classes in Java have a run-time representation and can perform run-time type checking.

The excellent characteristics of the Java language make Java applications extremely robust and reliable, which also reduces the maintenance costs of the application system. Java's comprehensive support for object technology and the API embedded in the Java platform can shorten application system development time and reduce costs. Java's compile-once-run-anywhere nature enables it to provide an open architecture that can be used anywhere and a low-cost way to transfer information between multiple platforms. In particular, Java Enterprise Application Programming Interfaces (Java Enterprise APIs) provide relevant technologies and rich class libraries for enterprise computing and e-commerce application systems.