How to implement Java underlying technology operating system calls and JNI. In Java programming, we usually use high-level language features and APIs for development. But sometimes, we need to access the underlying functions of the operating system to meet specific needs. In order to achieve this purpose, Java provides a mechanism-operating system calls and JNI (JavaNativeInterface). Operating system calls refer to Java programs accessing the underlying functions of the operating system by calling functions provided by the operating system. and

Description 1. The main function of jni. The jni standard has become part of the java platform since jdk1.1. It provides a series of APIs that allow java to interact with other languages, and enables calling functions of other languages ????in java code. 2. Normally we use jni to call code in c or c++. Example publicclassJniTest{static{System.loadLibrary("MyNativeDll");}publicstaticnativevoidcallCppMethod();publicstaticvoidmai

jni meaning: The main function of jni is that the jni standard has become part of the java platform since jdk1.1. It provides a series of APIs that allow java to interact with other languages, and enables calling functions of other languages ????in java code. Generally, we use jni to call code in c or c++. Usage example: publicclassJniTest{static{System.loadLibrary("MyNativeDll");}publicstaticnativevoidcallCppMethod();publicstaticvoidma

How to implement Java's underlying technology - JNI and native method calls. Java is a cross-platform programming language, but sometimes we need to interact with the underlying C or C++ code. In Java, we can access local methods through JNI (JavaNativeInterface) to communicate with the underlying code. This article will introduce how to use JNI to implement Java and native method calls, and provide some specific code examples. First, we need to prepare a Java class that

JNI (JavaNativeInterface) is a framework for allowing Java code running in the JVM to interact with applications and libraries written in other languages such as C, C or assembly. Its core uses include: 1. Improve performance key parts; 2. Integrate legacy systems; 3. Achieve hardware access; 4. Utilize platform-specific functions. When using it, you need to mark the native method and link it to the shared library. When called, the JVM will look for the corresponding function to execute, and at the same time operate the Java object through the JNIEnv pointer. Common problems include manual cleaning of memory management, validity of JNIEnv in threads, exception checking and naming specifications, and debugging requires combining tools such as jdb and GDB.

Common usage scenarios for JNI include improving the execution efficiency of performance-sensitive parts, accessing operating system or hardware-specific features, reusing existing local library resources, and enhancing security and anti-reverse protection. 1. For high-performance tasks such as image processing, encryption and decryption, C/C can be used to implement key logic through JNI to improve efficiency, but attention should be paid to cross-language call overhead; 2. When accessing device drivers, sensor data or system APIs is required, it can be implemented with the help of the JNI call platform related local libraries, and compatibility issues should be considered; 3. In order to reuse existing C/C code assets, it can be encapsulated through JNI for Java application calls to reduce duplicate development, but a reasonable interface should be designed; 4. Placing the key logic at the native layer can increase the reverse difficulty

JNI (JavaNativeInterface) is a framework that allows Java code to interact with local applications or libraries written in other languages ??such as C, C, or assembly. 1. Its main function is to serve as a bridge between Java and local code, so that Java can safely break through the isolation of JVM to access system resources; 2. Usage scenarios include calling high-performance mathematical libraries, connecting to platform-specific APIs, or encapsulating native SDKs; 3. The usage steps include declaring native methods, generating C/C header files, implementing and compiling into shared libraries, and loading the library in Java; 4. Notes include using JNI types for data type differences, operating Java objects must be done through JNI functions, and debugging.

JNI allows Java code to interact with local code written in C/C and other languages, and implement it as a shared library by declaring native methods, generating header files, writing and compiling C as a shared library, loading the library and running the program to achieve calls; 2. Data is converted between Java and local types through JNI functions, such as jstring and char*; 3. Local code can callback Java methods, and you need to obtain class references, method IDs and use functions such as CallVoidMethod; 4. When using it, you need to pay attention to naming specifications, exception checking, memory management, thread safety and performance overhead; 5. Applicable to access system resources, reusing native libraries or improving performance, but you should avoid using them when pure Java can solve or emphasize portability; JNI is strong