11 major features of java language

Java is a simple, object-oriented, distributed, interpreted, robust and safe, structure-neutral, portable, excellent-performance, multi-threaded static language. So what are the characteristics of the java language?

1. 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. Java language is an object-oriented

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 classes. The implementation mechanism between interfaces (keyword is implements). A Java training instructor at Xi'an Jiaotong University said that 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 a class library for network application programming. , including URL, URLConnection, Socket, ServerSocket, etc. Java's RMI (Remote Method Activation) mechanism is also an important means for 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. A Java training instructor at Xi'an Jiaotong University said that in addition to the many security features of the Java language, Java has a security prevention mechanism (ClassLoader) for classes downloaded through the network, such as allocating different name spaces to prevent the replacement of local classes with the same name. Byte code inspection, and provides a security management mechanism (class SecurityManager) to allow Java applications to set 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 then this can be implemented Runs on any system on the 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 stipulates 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 earlier, Java programs are compiled into bytecode format on the Java platform, and can then be run in 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, with the development of JIT (Just-In-Time) compiler technology, Java's running speed is getting closer and closer to C++.

10. The Java language is multi-threaded

In the Java language, a thread is a special object, which 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, or the required classes can 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.