JDK 11 jdk.jcmd.jmod is the JMOD file for JDK 11 JCmd tool, which can be invoked by the "jcmd" command.

JDK 11 JCmd tool compiled class files are stored in \fyicenter\jdk-11.0.1\jmods\jdk.jcmd.jmod.

JDK 11 JCmd tool compiled class files are also linked and stored in the \fyicenter\jdk-11.0.1\lib\modules JImage file.

JDK 11 JCmd source code files are stored in \fyicenter\jdk-11.0.1\lib\src.zip\jdk.jcmd.

You can click and view the content of each source code file in the list below.

⏎ sun/tools/jmap/JMap.java

/*
 * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package sun.tools.jmap;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Collection;

import com.sun.tools.attach.VirtualMachine;
import com.sun.tools.attach.VirtualMachineDescriptor;
import com.sun.tools.attach.AttachNotSupportedException;
import sun.tools.attach.HotSpotVirtualMachine;
import sun.tools.common.ProcessArgumentMatcher;

/*
 * This class is the main class for the JMap utility. It parses its arguments
 * and decides if the command should be satisfied using the VM attach mechanism
 * or an SA tool. At this time the only option that uses the VM attach mechanism
 * is the -dump option to get a heap dump of a running application. All other
 * options are mapped to SA tools.
 */
public class JMap {

    public static void main(String[] args) throws Exception {
        if (args.length == 0) {
            usage(1); // no arguments
        }

        checkForUnsupportedOptions(args);

        // the chosen option
        String option = null;

        // First iterate over the options (arguments starting with -).  There should be
        // one.
        int optionCount = 0;
        while (optionCount < args.length) {
            String arg = args[optionCount];
            if (!arg.startsWith("-")) {
                break;
            }
            if (arg.equals("-?") ||
                arg.equals("-h") ||
                arg.equals("--help") ||
                // -help: legacy. Undocumented.
                arg.equals("-help")) {
                usage(0);
            } else {
                if (option != null) {
                    usage(1);  // option already specified
                }
                option = arg;
            }
            optionCount++;
        }

        // if no option provided then use default.
        if (option == null) {
            usage(0);
        }

        // Next we check the parameter count.
        int paramCount = args.length - optionCount;
        if (paramCount != 1) {
            usage(1);
        }

        String pidArg = args[1];
        // Here we handle the built-in options
        // As more options are added we should create an abstract tool class and
        // have a table to map the options
        ProcessArgumentMatcher ap = new ProcessArgumentMatcher(pidArg);
        Collection<String> pids = ap.getVirtualMachinePids(JMap.class);

        if (pids.isEmpty()) {
            System.err.println("Could not find any processes matching : '" + pidArg + "'");
            System.exit(1);
        }

        for (String pid : pids) {
            if (pids.size() > 1) {
                System.out.println("Pid:" + pid);
            }
            if (option.equals("-histo")) {
                histo(pid, "");
            } else if (option.startsWith("-histo:")) {
                histo(pid, option.substring("-histo:".length()));
            } else if (option.startsWith("-dump:")) {
                dump(pid, option.substring("-dump:".length()));
            } else if (option.equals("-finalizerinfo")) {
                executeCommandForPid(pid, "jcmd", "GC.finalizer_info");
            } else if (option.equals("-clstats")) {
                executeCommandForPid(pid, "jcmd", "GC.class_stats");
            } else {
              usage(1);
            }
        }
    }

    private static void executeCommandForPid(String pid, String command, Object ... args)
        throws AttachNotSupportedException, IOException,
               UnsupportedEncodingException {
        VirtualMachine vm = VirtualMachine.attach(pid);

        // Cast to HotSpotVirtualMachine as this is an
        // implementation specific method.
        HotSpotVirtualMachine hvm = (HotSpotVirtualMachine) vm;
        try (InputStream in = hvm.executeCommand(command, args)) {
          // read to EOF and just print output
          byte b[] = new byte[256];
          int n;
          do {
              n = in.read(b);
              if (n > 0) {
                  String s = new String(b, 0, n, "UTF-8");
                  System.out.print(s);
              }
          } while (n > 0);
        }
        vm.detach();
    }

    private static void histo(String pid, String options)
        throws AttachNotSupportedException, IOException,
               UnsupportedEncodingException {
        String liveopt = "-all";
        if (options.equals("") || options.equals("all")) {
            //  pass
        }
        else if (options.equals("live")) {
            liveopt = "-live";
        }
        else {
            usage(1);
        }

        // inspectHeap is not the same as jcmd GC.class_histogram
        executeCommandForPid(pid, "inspectheap", liveopt);
    }

    private static void dump(String pid, String options)
        throws AttachNotSupportedException, IOException,
               UnsupportedEncodingException {

        String subopts[] = options.split(",");
        String filename = null;
        String liveopt = "-all";

        for (int i = 0; i < subopts.length; i++) {
            String subopt = subopts[i];
            if (subopt.equals("live")) {
                liveopt = "-live";
            } else if (subopt.startsWith("file=")) {
                // file=<file> - check that <file> is specified
                if (subopt.length() > 5) {
                    filename = subopt.substring(5);
                }
            }
        }

        if (filename == null) {
            usage(1);  // invalid options or no filename
        }

        // get the canonical path - important to avoid just passing
        // a "heap.bin" and having the dump created in the target VM
        // working directory rather than the directory where jmap
        // is executed.
        filename = new File(filename).getCanonicalPath();
        // dumpHeap is not the same as jcmd GC.heap_dump
        executeCommandForPid(pid, "dumpheap", filename, liveopt);
    }

    private static void checkForUnsupportedOptions(String[] args) {
        // Check arguments for -F, -m, and non-numeric value
        // and warn the user that SA is not supported anymore

        int paramCount = 0;

        for (String s : args) {
            if (s.equals("-F")) {
                SAOptionError("-F option used");
            }

            if (s.equals("-heap")) {
                SAOptionError("-heap option used");
            }

            /* Reimplemented using jcmd, output format is different
               from original one

            if (s.equals("-clstats")) {
                warnSA("-clstats option used");
            }

            if (s.equals("-finalizerinfo")) {
                warnSA("-finalizerinfo option used");
            }
            */

            if (! s.startsWith("-")) {
                paramCount += 1;
            }
        }

        if (paramCount > 1) {
            SAOptionError("More than one non-option argument");
        }
    }

    private static void SAOptionError(String msg) {
        System.err.println("Error: " + msg);
        System.err.println("Cannot connect to core dump or remote debug server. Use jhsdb jmap instead");
        System.exit(1);
    }

    // print usage message
    private static void usage(int exit) {
        System.err.println("Usage:");
        System.err.println("    jmap -clstats <pid>");
        System.err.println("        to connect to running process and print class loader statistics");
        System.err.println("    jmap -finalizerinfo <pid>");
        System.err.println("        to connect to running process and print information on objects awaiting finalization");
        System.err.println("    jmap -histo[:live] <pid>");
        System.err.println("        to connect to running process and print histogram of java object heap");
        System.err.println("        if the \"live\" suboption is specified, only count live objects");
        System.err.println("    jmap -dump:<dump-options> <pid>");
        System.err.println("        to connect to running process and dump java heap");
        System.err.println("    jmap -? -h --help");
        System.err.println("        to print this help message");
        System.err.println("");
        System.err.println("    dump-options:");
        System.err.println("      live         dump only live objects; if not specified,");
        System.err.println("                   all objects in the heap are dumped.");
        System.err.println("      format=b     binary format");
        System.err.println("      file=<file>  dump heap to <file>");
        System.err.println("");
        System.err.println("    Example: jmap -dump:live,format=b,file=heap.bin <pid>");
        System.exit(exit);
    }
}

⏎ sun/tools/jmap/JMap.java

Or download all of them as a single archive file:

File name: jdk.jcmd-11.0.1-src.zip
File size: 47892 bytes
Release date: 2018-11-04
Download 

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