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Java example source code file (DebugServer.java)

This example Java source code file (DebugServer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

debuggerexception, debugserver, error, hotspotagent, numberformatexception, rmi, runnable, string

The DebugServer.java Java example source code

/*
 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

package sun.jvm.hotspot;

import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.oops.*;

public class DebugServer {
  private void usage() {
    System.out.println("usage: java " + getClass().getName() + " <pid> [server id]");
    System.out.println("   or: java " + getClass().getName() + " <executable>  [server id]");
    System.out.println("\"pid\" must be the process ID of a HotSpot process.");
    System.out.println("If reading a core file, \"executable\" must (currently) be the");
    System.out.println("full path name to the precise java executable which generated");
    System.out.println("the core file (not, on Solaris, the \"java\" wrapper script in");
    System.out.println("the \"bin\" subdirectory of the JDK.)");
    System.out.println("The \"server id\" is a unique name for a specific remote debuggee.");
    System.exit(1);
  }

  public static void main(String[] args) {
    new DebugServer().run(args);
  }

  private void run(String[] args) {
    if ((args.length < 1) || (args.length > 3)) {
      usage();
    }

    // Attempt to handle "-h" or "-help"
    if (args[0].startsWith("-")) {
      usage();
    }

    int pid = 0;
    boolean usePid = false;
    String coreFileName = null;
    // FIXME: would be nice to pick this up from the core file
    // somehow, but that doesn't look possible. Should at least figure
    // it out from a path to the JDK.
    String javaExecutableName = null;
    String serverID = null;

    switch (args.length) {
       case 1:
         try {
           pid = Integer.parseInt(args[0]);
           usePid = true;
         } catch (NumberFormatException e) {
           usage();
         }
         break;

       case 2:
         // either we have pid and server id or exec file and core file
         try {
           pid = Integer.parseInt(args[0]);
           usePid = true;
           serverID = args[1];
         } catch (NumberFormatException e) {
           pid = -1;
           usePid = false;
           javaExecutableName = args[0];
           coreFileName = args[1];
         }
         break;

       case 3:
         javaExecutableName = args[0];
         coreFileName = args[1];
         serverID = args[2];
         break;

       default:
         // should not happend, taken care already.
         break;
    }

    final HotSpotAgent agent = new HotSpotAgent();
    try {
      if (usePid) {
        System.err.println("Attaching to process ID " + pid + " and starting RMI services, please wait...");
        agent.startServer(pid, serverID);
      } else {
        System.err.println("Attaching to core " + coreFileName +
                           " from executable " + javaExecutableName + " and starting RMI services, please wait...");
        agent.startServer(javaExecutableName, coreFileName, serverID);
      }
    }
    catch (DebuggerException e) {
      if (usePid) {
        System.err.print("Error attaching to process or starting server: ");
      } else {
        System.err.print("Error attaching to core file or starting server: ");
      }
      e.printStackTrace();
      System.exit(1);
    }

    // shutdown hook to clean-up the server in case of forced exit.
    Runtime.getRuntime().addShutdownHook(new java.lang.Thread(
                          new Runnable() {
                             public void run() {
                                agent.shutdownServer();
                             }
                          }));
    System.err.println("Debugger attached and RMI services started.");
  }
}

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