Java Articles - Page 176 of 745

JShell is a REPL tool that allows snippets of code to be run without placing them in classes. This tool provides a way to evaluate declarations, statements, and expressions in Java and no need to create the main() method to test some parts of the code.The command "/debug" can be used to display debugging information for the JShell tool implementation. Once we type the "/debug" command, the debugging mode is on. After enabling the debug mode and type something like a simple addition, or a simple string, then it prints as below.Example-1jshell> /debug | Debugging on jshell> 5+3 Compiling: 5+3 Kind: EXPRESSION_STATEMENT ... Read More

In this article, we will learn about the unified JVM logging in Java 9. Logging in the JVM is a great tool for performing root cause analysis, and it is a part of the JDK(Java Development Kit). Starting from JDK 9, the JVM maintainers chose to rebuild the way the JVM logs things. What is Unified JVM Logging? Java 9 can provide a common logging system for JVM components with a detailed level. By using a new command-line option: -Xlog for all logging settings, and unified JVM logging, gives us an easy-to-configure tool to do a root cause analysis (RCA) ... Read More

Since Java 9, versioning can be consistent with semantic versioning. The version number can be a non-empty sequence of strings separated by dots. It contains three major parts: major version number, minor version number, and security. The new versioning scheme has documented in Runtime. Version class and version information can be accessed from it.The version numbers have the below format:$MAJOR.$MINOR.$SECURITY(.$otherpart)?$MAJOR is the major version number and incremented when a major version has released that typically changes the platform specification. For JDK 9, this value is 9.$MINOR is the minor version number and incremented for releases that contain bug fixes and enhancements to ... Read More

Java 9 defines a StackWalker API that provides laziness and frame filtering. An object of StackWalker allows us to traverse and access stacks and contains one useful method: walk(). This method opens a StackFrame stream for the current thread, then applies the function with that StackFrame stream. We need to get StackWalker object, then use StackWalker.getInstance() method.In the below example, we can print different stack frames: all stack frames, skip some stack frames and limit stack frames by using StackWalker API.Exampleimport java.lang.StackWalker.StackFrame; import java.util.*; import java.util.stream.*; public class StackWalkerTest {    public static void main(String args[]) {       new StackWalkerTest().walk();    }    private void walk() {     ... Read More

In this article, we will learn to use the delayedExecutor() method of CompletableFuture in Java 9. We're gonna know about the delayedExecutor() method and also the CompletableFuture class, as this method belongs to this class, and we're gonna know the uses of the delayedExecutor() method along with an example. CompletableFuture Class The CompletableFuture Class was introduced in Java 8. CompletableFuture is a class in java.util.concurrent package that implements the Future and CompletionStage Interface. CompletableFuture provides a powerful and flexible way to write asynchronous, non-blocking code. It supports delays and timeouts. The delayedExecutor() Method The delayedExecutor() method has been added ... Read More

Since Java 9, we can create Reactive Streams by introducing four core interfaces: Publisher, Subscriber, Subscription, Processor, and one concrete class: SubmissionPublisher that implements the Publisher interface. Each interface plays a different role, corresponding to the principles of Reactive Streams. We can use the submit() method of SubmissionPublisher class to publish the provided item to each subscriber.Syntaxpublic class SubmissionPublisher extends Object implements Flow.Publisher, AutoCloseableIn the below example, we can implement the SubmissionPublisher classExampleimport java.util.concurrent.Flow.Subscriber; import java.util.concurrent.Flow.Subscription; import java.util.concurrent.SubmissionPublisher; class MySubscriber implements Subscriber {    private Subscription subscription;    private String name;    public MySubscriber(String name) {       this.name = name;   ... Read More

Java 9 has introduced Reactive Streams under java.util.concurrent.Flow package that supports an interoperable publish-subscribe framework. It processes an asynchronous stream of data across the asynchronous boundary (passing elements into another thread or thread-pool), and the receiving side is not forced to buffer arbitrary amounts of data, then buffer overflow can't occur.Flow API contains four interrelated core interfaces: Publisher, Subscriber, Subscription, and Processor.Syntax@FunctionalInterface public static interface Publisher {    public void subscribe(Subscriber

In Java 9, Process API has been used to control and manage operating system processes. ProcessHandle class provides the process’s native process ID, start time, accumulated CPU time, arguments, command, user, parent process, and descendants. It also provides a method to check processes liveness and to destroy processes. We retrieve all ProcessHandle data as a stream by using the allProcesses() method.In the below example, we retrieve all the processes information.Exampleimport java.util.stream.Stream; import java.util.Optional; import java.util.stream.Stream; public class AllProcessesTest {    public static void main(String args[]) throws InterruptedException {       System.out.println("---------------------------");       System.out.println("All Processes:");       Stream processStream = ProcessHandle.allProcesses();       processStream.forEach(process -> ... Read More

In this article, we will learn to get all children of a process using Process API in Java 9. First, we will learn about Process API and its methods, ProcessHandle interface and after that we will use the children method of the ProcessHandle interface. Process API In Java, the Process API, we can perform any operation regarding a process. The Process class provides methods for performing input on the processes, performing output to the processes, waiting for the process to complete, finding child and parent processes of the currently running process, getting any information about a process, and destroying the process. The ... Read More

In Java 9, Process API supports an easy way to get much information about a process. ProcessHandle interface can identify and provide the control of native processes and method to check processes liveness and destroy the processes whereas ProcessHandle.Info interface can give an Information snapshot of a process. We need to destroy a process by using the destroy() method of the ProcessHandle interface.In the below example, we need to terminate a process by using the ProcessHandle interface.Exampleimport java.io.File; import java.io.IOException; import java.util.Objects; public class DestroyProcessTest {    public static void main(String[] args) throws InterruptedException {       System.out.println("---------------------------");       ... Read More