/* * Copyright (c) 2005, 2025, 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * 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 com.sun.management; import java.io.IOException; import java.lang.management.PlatformManagedObject; /** * Diagnostic management interface for the HotSpot Virtual Machine. * *

The diagnostic MBean is registered to the platform MBeanServer * as are other platform MBeans. * *

The {@code ObjectName} for uniquely identifying the diagnostic * MXBean within an MBeanServer is: *

* {@code com.sun.management:type=HotSpotDiagnostic} *
* * It can be obtained by calling the * {@link PlatformManagedObject#getObjectName} method. * * All methods throw a {@code NullPointerException} if any input argument is * {@code null} unless it's stated otherwise. * * @see java.lang.management.ManagementFactory#getPlatformMXBeans(Class) * * @since 1.6 */ public interface HotSpotDiagnosticMXBean extends PlatformManagedObject { /** * Dumps the heap to the {@code outputFile} file in the same * format as the hprof heap dump. *

* If this method is called remotely from another process, * the heap dump output is written to a file named {@code outputFile} * on the machine where the target VM is running. If outputFile is * a relative path, it is relative to the working directory where * the target VM was started. * * @param outputFile the system-dependent filename * @param live if {@code true} dump only live objects * i.e. objects that are reachable from others * @throws IOException if the {@code outputFile} already exists, * cannot be created, opened, or written to. * @throws UnsupportedOperationException if this operation is not supported. * @throws IllegalArgumentException if {@code outputFile} does not end with ".hprof" suffix. * @throws NullPointerException if {@code outputFile} is {@code null}. */ public void dumpHeap(String outputFile, boolean live) throws IOException; /** * Returns a list of {@code VMOption} objects for all diagnostic options. * A diagnostic option is a {@link VMOption#isWriteable writeable} * VM option that can be set dynamically mainly for troubleshooting * and diagnosis. * * @return a list of {@code VMOption} objects for all diagnostic options. */ public java.util.List getDiagnosticOptions(); /** * Returns a {@code VMOption} object for a VM option of the given * name. * * @return a {@code VMOption} object for a VM option of the given name. * @throws NullPointerException if name is {@code null}. * @throws IllegalArgumentException if a VM option of the given name * does not exist. */ public VMOption getVMOption(String name); /** * Sets a VM option of the given name to the specified value. * The new value will be reflected in a new {@code VMOption} * object returned by the {@link #getVMOption} method or * the {@link #getDiagnosticOptions} method. This method does * not change the value of this {@code VMOption} object. * * @param name Name of a VM option * @param value New value of the VM option to be set * * @throws IllegalArgumentException if the VM option of the given name * does not exist. * @throws IllegalArgumentException if the new value is invalid. * @throws IllegalArgumentException if the VM option is not writable. * @throws NullPointerException if name or value is {@code null}. */ public void setVMOption(String name, String value); /** * Generate a thread dump to the given file in the given format. The * {@code outputFile} parameter must be an absolute path to a file that * does not exist. * *

When the format is specified as {@link ThreadDumpFormat#JSON JSON}, the * thread dump is generated in JavaScript Object Notation. * threadDump.schema.json * describes the thread dump format in draft * * JSON Schema Language version 2. * *

The thread dump will include output for all platform threads. It may * include output for some or all virtual threads. * * @implSpec * The default implementation throws {@code UnsupportedOperationException}. * * @apiNote * The output file is required to be an absolute path as the MXBean may be * accessed remotely from a tool or program with a different current working * directory. * * @param outputFile the path to the file to create * @param format the format to use * @throws IllegalArgumentException if the file path is not absolute * @throws IOException if the file already exists or an I/O exception is * thrown writing to the file * @throws NullPointerException if either parameter is {@code null} * @throws UnsupportedOperationException if this operation is not supported * @since 21 */ default void dumpThreads(String outputFile, ThreadDumpFormat format) throws IOException { throw new UnsupportedOperationException(); } /** * Thread dump format. * @since 21 */ public static enum ThreadDumpFormat { /** * Plain text format. */ TEXT_PLAIN, /** * JSON (JavaScript Object Notation) format. * @spec https://datatracker.ietf.org/doc/html/rfc8259 JavaScript Object Notation */ JSON, } }