JavaLangRuntime

JavaLangRuntime is a class within the Java Development Kit (JDK) that represents the runtime environment of the Java Virtual Machine (JVM). It provides access to various properties and methods related to the JVM's operation. Instances of the Runtime class are typically obtained through the static getRuntime() method.

Key functionalities of the Runtime class include managing memory, executing external processes, and accessing information about the operating system and the Java version. For instance, developers can use methods like freeMemory() and totalMemory() to monitor the JVM's memory usage, and exec() to run commands on the underlying operating system. The loadLibrary() method allows for the loading of native libraries.

The Runtime class also provides methods for terminating the Java application, such as exit() and halt(). While exit() performs a normal shutdown by running shutdown hooks and flushing streams, halt() is a more abrupt termination. Additionally, it offers information about the garbage collector and the ability to explicitly trigger garbage collection through the gc() method.

It's important to note that the Runtime class is inherently tied to a specific JVM instance. Direct instantiation of the Runtime class is not permitted; developers must always use the getRuntime() method to obtain the single instance associated with the running JVM. This class is part of the java.lang package, which is automatically imported into all Java programs.