Java. lang Package Overview (3)

Java. Lang. Object
This class object is the root of all other class object extension hierarchy trees on the Java platform. All other classes extend the class either directly or indirectly. This class provides the default object operation method:
Clone ()
Returns a duplicate of the object.
Equals ()
Compare whether the object is "equal" to the specified object. The comparison rules depend entirely on the implementation of each class.
Finalize ()
This method is called when the Garbage Collector recycles this object.
Getclass ()
Returns the runtime class of the object.
Hashcode ()
Returns the hash of the object. Code Value. Different objects return different values. Therefore, this value can be used to uniquely identify an object.
Notify ()
Any thread that monitors this object is awakened from the waiting thread set of this object. There are three methods to monitor an object (OBJ): one is to execute the synchronization method of OBJ; the other is to execute the synchronization method of OBJ objects; the third is to execute the synchronization code segment of obj.
Policyall ()
From the waiting thread of the object, all threads that monitor the object are automatically awakened. Each thread obtains the ownership of the object monitor through competition and continues to execute the paused action.
Tostring ()
Returns the string description of the object.
Wait ()
Pause the current thread and place the thread in the waiting thread set of the object until the current thread is awakened to continue execution.
Wait (timeout)
Pause the current thread and place it in the waiting thread set of the object until the current thread is awakened or continues execution after a specified timeout period.
Java. Lang. Package
The object of this class contains the specification and implementation version information that has been followed by the encapsulated Java package. The information mainly comes from the manifest file deployed together with the class file. Class classloader is responsible for obtaining this information. The standard version number complies with the "/d + (/./d +) *" mode.
Java. Lang. Process
Executive
The row processbuilder.start((and runtime.exe C () methods can be used to obtain instances of subclass of this class. These instance objects can be used to obtain process information and
Process control. This class provides methods to get input from a process, output to the process, wait for the process to complete, check the process end status, and kill the process. Interaction with a process through the standard Io method of the process
(Stdin, stdout, stderr.
Java. Lang. processbuilderclassname
Create an operating system process to execute External commands. It also allows you to provide parameters for command execution and set system environment variables.
Java. Lang. Runtime
Each Java application has only one instance of this class. Through such instances, Java applications can interact with the Virtual Machine runtime environment.
Java. Lang. runtimepermission
Runtime permission. It is used to determine whether certain actions can be executed during running.
Java. Lang. securitymanager
Security Manager. Provides applications with services that verify that they have certain permissions in a specific security context.
Java. Lang. Short
Class that visualizes the original data type short. In addition to a short value, the instance object of this class also provides short-type conversion and other short processing methods.