【正文】 Debug Java applications remotely with Eclipse Use the power of the Eclipse IDE to spread around your Java application debugging Level: Intermediate Charles Lu (), Software Engineer, IBM 09 Dec 2020 You don39。t need to debug Java? applications on just your local desktop. Learn how to spread around your debugging using different connection types that make up remote debugging. This article explains the features and examples that show how to set up remote application debugging. Remote debugging can be useful for application development, such as developing a program for a lowend machine that cannot host the development platform, or debugging programs on dedicated machines like Web servers, whose services cannot be shut down. Other examples include Java applications running with limited memory or CPU power, such as mobile devices, or developers wanting to separate the application and development environments, etc. Prerequisites If you don39。t have it already, download Eclipse (Ganymede). In Ganymede, the socket listening connector has been added to the Remote Java Application launchconfiguration type. Eclipse39。s new socket listening connector allows you to start the Java debugger, which listens for a connection on a specific socket. The program being debugged can then be started with mandline options to connect to the debugger. Prior to the Ganymede release, only a socketattaching connector was provided, and the program being debugged had to be a debug host that was connected by the debugger. It is impractical for mobile devices to be a host due to insufficient memory and CPU power. To use remote debugging, Java Virtual Machine (JVM) or later must be used, such as IBM174。 J9 or Sun Microsystems39。 Java SE Development Kit (JDK). In this article, we focus on remote debugging, rather than detail each of Eclipse39。s debugging features. See Resources for more information about debugging with Eclipse and where to find the aforementioned software. JPDA introduction Sun Microsystems39。 Java Platform Debugger Architecture (JPDA) technology is a multitiered architecture that allows you to debug Java applications in all situations easily. The JPDA consists of two interfaces (the JVM Tool Interface and JDI, respectively), a protocol (Java Debug Wire Protocol), and two software ponents that tie them together (backend and frontend). It39。s designed for use by debuggers in any environment. JPDA is not only for desktop systems but works well with embedded systems, too. The JVM Tool Interface (JVMTI) defines that a VM must provide for debugging. (Editor39。s note: Starting with Java V5, JVMTI replaced JVMDI, which was used in Java .) The Java Debug Wire Protocol (JDWP) describes the format of debugging information and requests transferred between the process being debugged and a debugger front end, which implements the JDI, such as Eclipse, Borland JBuilder, and Launchconfiguration type A launch configuration keeps a set of attributes that can be used to launch a program. The launchconfiguration type is a unique type of program that can be launched in the Eclipse platform. Frequently used acronyms ? JDI — Java Debug Interface ? JDT — Java Development Tools ? JDWP — Java Debug Wire Protocol ? JPDA — Java Platform Debugger Architecture ? JVM — Java Virtual Machine ? JVMDI — JVM Debug Interface ? JVMTI — JVM Tool Interface ? VM — Virtual Machine many others. The program being debugged is often called the debuggee in Sun39。s JPDA specification. The JDI is a highlevel interface to define the information and requests used for remote debugging. The architecture is structured as follows. Listing 1. The Java Platform Debugger Architecture Components Debugger Interfaces / || / | VM | debuggee ( || JVMTI Java VM Tool Interface \ | backend | \ || / | m channel ( | JDWP Java Debug Wire Protocol \ | / || / | frontend | debugger ( || JDI Java Debug Interface \ | UI | \ || Therefore, any thirdparty tools and VM based on JPDA should work together without plaint. This clientserver architecture allows you to debug a Java program from a local workstation running the platform, or even debug it from a remote puter on your work. Before talking about the debugscenario stuff, we need to introduce two terms used in the JPDA specification: connector and transport. A connector is a JDI abstraction used to establish a connection between a debugger application and a target VM. A transport defines how applications access and transmit data between the front end and back end. The connectors map to the available transport types and the modes of connection. In Sun39。s reference implementati