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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.misc; | ||
| 27 | |||
| 28 | import static java.lang.Thread.State.*; | ||
| 29 | import java.util.Properties; | ||
| 30 | import java.util.HashMap; | ||
| 31 | import java.util.Map; | ||
| 32 | import java.util.Set; | ||
| 33 | |||
| 34 | public class VM { | ||
| 35 | |||
| 36 | /* The following methods used to be native methods that instruct | ||
| 37 | * the VM to selectively suspend certain threads in low-memory | ||
| 38 | * situations. They are inherently dangerous and not implementable | ||
| 39 | * on native threads. We removed them in JDK 1.2. The skeletons | ||
| 40 | * remain so that existing applications that use these methods | ||
| 41 | * will still work. | ||
| 42 | */ | ||
| 43 | private static boolean suspended = false; | ||
| 44 | |||
| 45 | /** @deprecated */ | ||
| 46 | @Deprecated | ||
| 47 | public static boolean threadsSuspended() { | ||
| 48 | return suspended; | ||
| 49 | } | ||
| 50 | |||
| 51 | public static boolean allowThreadSuspension(ThreadGroup g, boolean b) { | ||
| 52 | return g.allowThreadSuspension(b); | ||
| 53 | } | ||
| 54 | |||
| 55 | /** @deprecated */ | ||
| 56 | @Deprecated | ||
| 57 | public static boolean suspendThreads() { | ||
| 58 | suspended = true; | ||
| 59 | return true; | ||
| 60 | } | ||
| 61 | |||
| 62 | // Causes any suspended threadgroups to be resumed. | ||
| 63 | /** @deprecated */ | ||
| 64 | @Deprecated | ||
| 65 | public static void unsuspendThreads() { | ||
| 66 | suspended = false; | ||
| 67 | } | ||
| 68 | |||
| 69 | // Causes threadgroups no longer marked suspendable to be resumed. | ||
| 70 | /** @deprecated */ | ||
| 71 | @Deprecated | ||
| 72 | public static void unsuspendSomeThreads() { | ||
| 73 | } | ||
| 74 | |||
| 75 | /* Deprecated fields and methods -- Memory advice not supported in 1.2 */ | ||
| 76 | |||
| 77 | /** @deprecated */ | ||
| 78 | @Deprecated | ||
| 79 | public static final int STATE_GREEN = 1; | ||
| 80 | |||
| 81 | /** @deprecated */ | ||
| 82 | @Deprecated | ||
| 83 | public static final int STATE_YELLOW = 2; | ||
| 84 | |||
| 85 | /** @deprecated */ | ||
| 86 | @Deprecated | ||
| 87 | public static final int STATE_RED = 3; | ||
| 88 | |||
| 89 | /** @deprecated */ | ||
| 90 | @Deprecated | ||
| 91 | public static final int getState() { | ||
| 92 | return STATE_GREEN; | ||
| 93 | } | ||
| 94 | |||
| 95 | /** @deprecated */ | ||
| 96 | @Deprecated | ||
| 97 | public static void registerVMNotification(VMNotification n) { } | ||
| 98 | |||
| 99 | /** @deprecated */ | ||
| 100 | @Deprecated | ||
| 101 | public static void asChange(int as_old, int as_new) { } | ||
| 102 | |||
| 103 | /** @deprecated */ | ||
| 104 | @Deprecated | ||
| 105 | public static void asChange_otherthread(int as_old, int as_new) { } | ||
| 106 | |||
| 107 | /* | ||
| 108 | * Not supported in 1.2 because these will have to be exported as | ||
| 109 | * JVM functions, and we are not sure we want do that. Leaving | ||
| 110 | * here so it can be easily resurrected -- just remove the // | ||
| 111 | * comments. | ||
| 112 | */ | ||
| 113 | |||
| 114 | /** | ||
| 115 | * Resume Java profiling. All profiling data is added to any | ||
| 116 | * earlier profiling, unless <code>resetJavaProfiler</code> is | ||
| 117 | * called in between. If profiling was not started from the | ||
| 118 | * command line, <code>resumeJavaProfiler</code> will start it. | ||
| 119 | * <p> | ||
| 120 | * | ||
| 121 | * NOTE: Profiling must be enabled from the command line for a | ||
| 122 | * java.prof report to be automatically generated on exit; if not, | ||
| 123 | * writeJavaProfilerReport must be invoked to write a report. | ||
| 124 | * | ||
| 125 | * @see resetJavaProfiler | ||
| 126 | * @see writeJavaProfilerReport | ||
| 127 | */ | ||
| 128 | |||
| 129 | // public native static void resumeJavaProfiler(); | ||
| 130 | |||
| 131 | /** | ||
| 132 | * Suspend Java profiling. | ||
| 133 | */ | ||
| 134 | // public native static void suspendJavaProfiler(); | ||
| 135 | |||
| 136 | /** | ||
| 137 | * Initialize Java profiling. Any accumulated profiling | ||
| 138 | * information is discarded. | ||
| 139 | */ | ||
| 140 | // public native static void resetJavaProfiler(); | ||
| 141 | |||
| 142 | /** | ||
| 143 | * Write the current profiling contents to the file "java.prof". | ||
| 144 | * If the file already exists, it will be overwritten. | ||
| 145 | */ | ||
| 146 | // public native static void writeJavaProfilerReport(); | ||
| 147 | |||
| 148 | |||
| 149 | private static volatile boolean booted = false; | ||
| 150 | |||
| 151 | // Invoked by by System.initializeSystemClass just before returning. | ||
| 152 | // Subsystems that are invoked during initialization can check this | ||
| 153 | // property in order to avoid doing things that should wait until the | ||
| 154 | // application class loader has been set up. | ||
| 155 | // | ||
| 156 | public static void booted() { | ||
| 157 | booted = true; | ||
| 158 | } | ||
| 159 | |||
| 160 | public static boolean isBooted() { | ||
| 161 | return booted; | ||
| 162 | } | ||
| 163 | |||
| 164 | // A user-settable upper limit on the maximum amount of allocatable direct | ||
| 165 | // buffer memory. This value may be changed during VM initialization if | ||
| 166 | // "java" is launched with "-XX:MaxDirectMemorySize=<size>". | ||
| 167 | // | ||
| 168 | // The initial value of this field is arbitrary; during JRE initialization | ||
| 169 | // it will be reset to the value specified on the command line, if any, | ||
| 170 | // otherwise to Runtime.getRuntime.maxDirectMemory(). | ||
| 171 | // | ||
| 172 | private static long directMemory = 64 * 1024 * 1024; | ||
| 173 | |||
| 174 | // Returns the maximum amount of allocatable direct buffer memory. | ||
| 175 | // The directMemory variable is initialized during system initialization | ||
| 176 | // in the saveAndRemoveProperties method. | ||
| 177 | // | ||
| 178 | public static long maxDirectMemory() { | ||
| 179 | return directMemory; | ||
| 180 | } | ||
| 181 | |||
| 182 | // User-controllable flag that determines if direct buffers should be page | ||
| 183 | // aligned. The "-XX:+PageAlignDirectMemory" option can be used to force | ||
| 184 | // buffers, allocated by ByteBuffer.allocateDirect, to be page aligned. | ||
| 185 | private static boolean pageAlignDirectMemory; | ||
| 186 | |||
| 187 | // Returns {@code true} if the direct buffers should be page aligned. This | ||
| 188 | // variable is initialized by saveAndRemoveProperties. | ||
| 189 | public static boolean isDirectMemoryPageAligned() { | ||
| 190 | return pageAlignDirectMemory; | ||
| 191 | } | ||
| 192 | |||
| 193 | // A user-settable boolean to determine whether ClassLoader.loadClass should | ||
| 194 | // accept array syntax. This value may be changed during VM initialization | ||
| 195 | // via the system property "sun.lang.ClassLoader.allowArraySyntax". | ||
| 196 | // | ||
| 197 | // The default for 1.5 is "true", array syntax is allowed. In 1.6, the | ||
| 198 | // default will be "false". The presence of this system property to | ||
| 199 | // control array syntax allows applications the ability to preview this new | ||
| 200 | // behaviour. | ||
| 201 | // | ||
| 202 | private static boolean defaultAllowArraySyntax = false; | ||
| 203 | private static boolean allowArraySyntax = defaultAllowArraySyntax; | ||
| 204 | |||
| 205 | // The allowArraySyntax boolean is initialized during system initialization | ||
| 206 | // in the saveAndRemoveProperties method. | ||
| 207 | // | ||
| 208 | // It is initialized based on the value of the system property | ||
| 209 | // "sun.lang.ClassLoader.allowArraySyntax". If the system property is not | ||
| 210 | // provided, the default for 1.5 is "true". In 1.6, the default will be | ||
| 211 | // "false". If the system property is provided, then the value of | ||
| 212 | // allowArraySyntax will be equal to "true" if Boolean.parseBoolean() | ||
| 213 | // returns "true". Otherwise, the field will be set to "false". | ||
| 214 | // | ||
| 215 | public static boolean allowArraySyntax() { | ||
| 216 | return allowArraySyntax; | ||
| 217 | } | ||
| 218 | |||
| 219 | /** | ||
| 220 | * Returns the system property of the specified key saved at | ||
| 221 | * system initialization time. This method should only be used | ||
| 222 | * for the system properties that are not changed during runtime. | ||
| 223 | * It accesses a private copy of the system properties so | ||
| 224 | * that user's locking of the system properties object will not | ||
| 225 | * cause the library to deadlock. | ||
| 226 | * | ||
| 227 | * Note that the saved system properties do not include | ||
| 228 | * the ones set by sun.misc.Version.init(). | ||
| 229 | * | ||
| 230 | */ | ||
| 231 | public static String getSavedProperty(String key) { | ||
| 232 | if (savedProps.isEmpty()) | ||
| 233 | throw new IllegalStateException("Should be non-empty if initialized"); | ||
| 234 | |||
| 235 | return savedProps.getProperty(key); | ||
| 236 | } | ||
| 237 | |||
| 238 | // TODO: the Property Management needs to be refactored and | ||
| 239 | // the appropriate prop keys need to be accessible to the | ||
| 240 | // calling classes to avoid duplication of keys. | ||
| 241 | private static final Properties savedProps = new Properties(); | ||
| 242 | |||
| 243 | // Save a private copy of the system properties and remove | ||
| 244 | // the system properties that are not intended for public access. | ||
| 245 | // | ||
| 246 | // This method can only be invoked during system initialization. | ||
| 247 | public static void saveAndRemoveProperties(Properties props) { | ||
| 248 | if (booted) | ||
| 249 | throw new IllegalStateException("System initialization has completed"); | ||
| 250 | |||
| 251 | savedProps.putAll(props); | ||
| 252 | |||
| 253 | // Set the maximum amount of direct memory. This value is controlled | ||
| 254 | // by the vm option -XX:MaxDirectMemorySize=<size>. | ||
| 255 | // The maximum amount of allocatable direct buffer memory (in bytes) | ||
| 256 | // from the system property sun.nio.MaxDirectMemorySize set by the VM. | ||
| 257 | // The system property will be removed. | ||
| 258 | String s = (String)props.remove("sun.nio.MaxDirectMemorySize"); | ||
| 259 | if (s != null) { | ||
| 260 | if (s.equals("-1")) { | ||
| 261 | // -XX:MaxDirectMemorySize not given, take default | ||
| 262 | directMemory = Runtime.getRuntime().maxMemory(); | ||
| 263 | } else { | ||
| 264 | long l = Long.parseLong(s); | ||
| 265 | if (l > -1) | ||
| 266 | directMemory = l; | ||
| 267 | } | ||
| 268 | } | ||
| 269 | |||
| 270 | // Check if direct buffers should be page aligned | ||
| 271 | s = (String)props.remove("sun.nio.PageAlignDirectMemory"); | ||
| 272 | if ("true".equals(s)) | ||
| 273 | pageAlignDirectMemory = true; | ||
| 274 | |||
| 275 | // Set a boolean to determine whether ClassLoader.loadClass accepts | ||
| 276 | // array syntax. This value is controlled by the system property | ||
| 277 | // "sun.lang.ClassLoader.allowArraySyntax". | ||
| 278 | s = props.getProperty("sun.lang.ClassLoader.allowArraySyntax"); | ||
| 279 | allowArraySyntax = (s == null | ||
| 280 | ? defaultAllowArraySyntax | ||
| 281 | : Boolean.parseBoolean(s)); | ||
| 282 | |||
| 283 | // Remove other private system properties | ||
| 284 | // used by java.lang.Integer.IntegerCache | ||
| 285 | props.remove("java.lang.Integer.IntegerCache.high"); | ||
| 286 | |||
| 287 | // used by java.util.zip.ZipFile | ||
| 288 | props.remove("sun.zip.disableMemoryMapping"); | ||
| 289 | |||
| 290 | // used by sun.launcher.LauncherHelper | ||
| 291 | props.remove("sun.java.launcher.diag"); | ||
| 292 | } | ||
| 293 | |||
| 294 | // Initialize any miscellenous operating system settings that need to be | ||
| 295 | // set for the class libraries. | ||
| 296 | // | ||
| 297 | public static void initializeOSEnvironment() { | ||
| 298 | if (!booted) { | ||
| 299 | OSEnvironment.initialize(); | ||
| 300 | } | ||
| 301 | } | ||
| 302 | |||
| 303 | /* Current count of objects pending for finalization */ | ||
| 304 | private static volatile int finalRefCount = 0; | ||
| 305 | |||
| 306 | /* Peak count of objects pending for finalization */ | ||
| 307 | private static volatile int peakFinalRefCount = 0; | ||
| 308 | |||
| 309 | /* | ||
| 310 | * Gets the number of objects pending for finalization. | ||
| 311 | * | ||
| 312 | * @return the number of objects pending for finalization. | ||
| 313 | */ | ||
| 314 | public static int getFinalRefCount() { | ||
| 315 | return finalRefCount; | ||
| 316 | } | ||
| 317 | |||
| 318 | /* | ||
| 319 | * Gets the peak number of objects pending for finalization. | ||
| 320 | * | ||
| 321 | * @return the peak number of objects pending for finalization. | ||
| 322 | */ | ||
| 323 | public static int getPeakFinalRefCount() { | ||
| 324 | return peakFinalRefCount; | ||
| 325 | } | ||
| 326 | |||
| 327 | /* | ||
| 328 | * Add <tt>n</tt> to the objects pending for finalization count. | ||
| 329 | * | ||
| 330 | * @param n an integer value to be added to the objects pending | ||
| 331 | * for finalization count | ||
| 332 | */ | ||
| 333 | public static void addFinalRefCount(int n) { | ||
| 334 | // The caller must hold lock to synchronize the update. | ||
| 335 | |||
| 336 | finalRefCount += n; | ||
| 337 | if (finalRefCount > peakFinalRefCount) { | ||
| 338 | peakFinalRefCount = finalRefCount; | ||
| 339 | } | ||
| 340 | } | ||
| 341 | |||
| 342 | /** | ||
| 343 | * Returns Thread.State for the given threadStatus | ||
| 344 | */ | ||
| 345 | public static Thread.State toThreadState(int threadStatus) { | ||
| 346 | if ((threadStatus & JVMTI_THREAD_STATE_RUNNABLE) != 0) { | ||
| 347 | return RUNNABLE; | ||
| 348 | } else if ((threadStatus & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) != 0) { | ||
| 349 | return BLOCKED; | ||
| 350 | } else if ((threadStatus & JVMTI_THREAD_STATE_WAITING_INDEFINITELY) != 0) { | ||
| 351 | return WAITING; | ||
| 352 | } else if ((threadStatus & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) != 0) { | ||
| 353 | return TIMED_WAITING; | ||
| 354 | } else if ((threadStatus & JVMTI_THREAD_STATE_TERMINATED) != 0) { | ||
| 355 | return TERMINATED; | ||
| 356 | } else if ((threadStatus & JVMTI_THREAD_STATE_ALIVE) == 0) { | ||
| 357 | return NEW; | ||
| 358 | } else { | ||
| 359 | return RUNNABLE; | ||
| 360 | } | ||
| 361 | } | ||
| 362 | |||
| 363 | /* The threadStatus field is set by the VM at state transition | ||
| 364 | * in the hotspot implementation. Its value is set according to | ||
| 365 | * the JVM TI specification GetThreadState function. | ||
| 366 | */ | ||
| 367 | private final static int JVMTI_THREAD_STATE_ALIVE = 0x0001; | ||
| 368 | private final static int JVMTI_THREAD_STATE_TERMINATED = 0x0002; | ||
| 369 | private final static int JVMTI_THREAD_STATE_RUNNABLE = 0x0004; | ||
| 370 | private final static int JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER = 0x0400; | ||
| 371 | private final static int JVMTI_THREAD_STATE_WAITING_INDEFINITELY = 0x0010; | ||
| 372 | private final static int JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT = 0x0020; | ||
| 373 | |||
| 374 | static { | ||
| 375 | initialize(); | ||
| 376 | } | ||
| 377 | private native static void initialize(); | ||
| 378 | } | ||