Runnable and Thread
今天看了源码，总算多少理解一点，对Runnable 和 Thread的区别
一句话，Runnable是接口，Thread 继承了Runnable, 它们都有run()方法。
public interface Runnable {
/**
* When an object implementing interface <code>Runnable</code> is used
* to create a thread, starting the thread causes the object's
* <code>run</code> method to be called in that separately executing
* thread.
* <p>
* The general contract of the method <code>run</code> is that it may
* take any action whatsoever.
*
* @see java.lang.Thread#run()
*/
public abstract void run();
}
public class Thread implements Runnable {
/* Make sure registerNatives is the first thing <clinit> does. */
private static native void registerNatives();
static {
registerNatives();
}
private char name[];
private int priority;
private Thread threadQ;
private long eetop;
/* Whether or not to single_step this thread. */
private boolean single_step;
/* Whether or not the thread is a daemon thread. */
private boolean daemon = false;
/* JVM state */
private boolean stillborn = false;
/* What will be run. */
private Runnable target;
/* The group of this thread */
private ThreadGroup group;
/* The context ClassLoader for this thread */
private ClassLoader contextClassLoader;
/* The inherited AccessControlContext of this thread */
private AccessControlContext inheritedAccessControlContext;
/* For autonumbering anonymous threads. */
private static int threadInitNumber;
private static synchronized int nextThreadNum() {
return threadInitNumber++;
}
ThreadLocal.ThreadLocalMap threadLocals = null;
ThreadLocal.ThreadLocalMap inheritableThreadLocals = null;
/*
* The requested stack size for this thread, or 0 if the creator did not
* specify a stack size. It is up to the VM to do whatever it likes with
* this number; some VMs will ignore it.
*/
private long stackSize;
/*
* JVM-private state that persists after native thread termination.
*/
private long nativeParkEventPointer;
private long tid;
private int threadStatus = 0;
/* For generating thread ID */
private static long threadSeqNumber;
private static synchronized long nextThreadID() {
return ++threadSeqNumber;
}
/**
* The argument supplied to the current call to
* java.util.concurrent.locks.LockSupport.park. Set by (private)
* java.util.concurrent.locks.LockSupport.setBlocker Accessed using
* java.util.concurrent.locks.LockSupport.getBlocker
*/
volatile Object parkBlocker;
/*
* The object in which this thread is blocked in an interruptible I/O
* operation, if any. The blocker's interrupt method should be invoked after
* setting this thread's interrupt status.
*/
private volatile Interruptible blocker;
private Object blockerLock = new Object();
/*
* Set the blocker field; invoked via sun.misc.SharedSecrets from java.nio
* code
*/
void blockedOn(Interruptible b) {
synchronized (blockerLock) {
blocker = b;
}
}
public final static int MIN_PRIORITY = 1;
public final static int NORM_PRIORITY = 5;
public final static int MAX_PRIORITY = 10;
/* If stop was called before start */
private boolean stopBeforeStart;
/* Remembered Throwable from stop before start */
private Throwable throwableFromStop;
/**
* Returns a reference to the currently executing thread object.
*
* @return the currently executing thread.
*/
public static native Thread currentThread();
/**
* Causes the currently executing thread object to temporarily pause and
* allow other threads to execute.
*/
public static native void yield();
/**
* Causes the currently executing thread to sleep (temporarily cease
* execution) for the specified number of milliseconds, subject to the
* precision and accuracy of system timers and schedulers. The thread does
* not lose ownership of any monitors.
*
* @param millis
* the length of time to sleep in milliseconds.
* @exception InterruptedException
* if any thread has interrupted the current thread. The
* <i>interrupted status</i> of the current thread is cleared
* when this exception is thrown.
* @see Object#notify()
*/
public static native void sleep(long millis) throws InterruptedException;
/**
* Causes the currently executing thread to sleep (cease execution) for the
* specified number of milliseconds plus the specified number of
* nanoseconds, subject to the precision and accuracy of system timers and
* schedulers. The thread does not lose ownership of any monitors.
*
* @param millis
* the length of time to sleep in milliseconds.
* @param nanos
* 0-999999 additional nanoseconds to sleep.
* ...
*/
public static void sleep(long millis, int nanos)
throws InterruptedException {
if (millis < 0) {
throw new IllegalArgumentException("timeout value is negative");
}
if (nanos < 0 || nanos > 999999) {
throw new IllegalArgumentException(
"nanosecond timeout value out of range");
}
if (nanos >= 500000 || (nanos != 0 && millis == 0)) {
millis++;
}
sleep(millis);
}
/**
* Initializes a Thread.
* ...
*/
private void init(ThreadGroup g, Runnable target, String name,
long stackSize) {
Thread parent = currentThread();
SecurityManager security = System.getSecurityManager();
if (g == null) {
if (security != null) {
g = security.getThreadGroup();
}
if (g == null) {
g = parent.getThreadGroup();
}
}
/*
* checkAccess regardless of whether or not threadgroup is explicitly
* passed in.
*/
g.checkAccess();
/*
* Do we have the required permissions?
*/
if (security != null) {
if (isCCLOverridden(getClass())) {
security.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
}
}
g.addUnstarted();
this.group = g;
this.daemon = parent.isDaemon();
this.priority = parent.getPriority();
this.name = name.toCharArray();
if (security == null || isCCLOverridden(parent.getClass()))
this.contextClassLoader = parent.getContextClassLoader();
else
this.contextClassLoader = parent.contextClassLoader;
this.inheritedAccessControlContext = AccessController.getContext();
this.target = target;
setPriority(priority);
if (parent.inheritableThreadLocals != null)
this.inheritableThreadLocals = ThreadLocal
.createInheritedMap(parent.inheritableThreadLocals);
/* Stash the specified stack size in case the VM cares */
this.stackSize = stackSize;
/* Set thread ID */
tid = nextThreadID();
}
public Thread() {
init(null, null, "Thread-" + nextThreadNum(), 0);
}
public Thread(Runnable target) {
init(null, target, "Thread-" + nextThreadNum(), 0);
}
public Thread(ThreadGroup group, Runnable target) {
init(group, target, "Thread-" + nextThreadNum(), 0);
}
public Thread(String name) {
init(null, null, name, 0);
}
public Thread(ThreadGroup group, String name) {
init(group, null, name, 0);
}
public Thread(Runnable target, String name) {
init(null, target, name, 0);
}
public Thread(ThreadGroup group, Runnable target, String name) {
init(group, target, name, 0);
}
public Thread(ThreadGroup group, Runnable target, String name,
long stackSize) {
init(group, target, name, stackSize);
}
/**
* Causes this thread to begin execution; the Java Virtual Machine calls the
* <code>run</code> method of this thread.
* <p>
* The result is that two threads are running concurrently: the current
* thread (which returns from the call to the <code>start</code> method) and
* the other thread (which executes its <code>run</code> method).
* <p>
* It is never legal to start a thread more than once. In particular, a
* thread may not be restarted once it has completed execution.
*
* @exception IllegalThreadStateException
* if the thread was already started.
* @see #run()
* @see #stop()
*/
public synchronized void start() {
/**
* This method is not invoked for the main method thread or "system"
* group threads created/set up by the VM. Any new functionality added
* to this method in the future may have to also be added to the VM.
*
* A zero status value corresponds to state "NEW".
*/
if (threadStatus != 0)
throw new IllegalThreadStateException();
group.add(this);
start0();
if (stopBeforeStart) {
stop0(throwableFromStop);
}
}
private native void start0();
/**
* If this thread was constructed using a separate <code>Runnable</code> run
* object, then that <code>Runnable</code> object's <code>run</code> method
* is called; otherwise, this method does nothing and returns.
* <p>
* Subclasses of <code>Thread</code> should override this method.
*
* @see #start()
* @see #stop()
* @see #Thread(ThreadGroup, Runnable, String)
*/
public void run() {
if (target != null) {
target.run();
}
}
/**
* This method is called by the system to give a Thread a chance to clean up
* before it actually exits.
*/
private void exit() {
if (group != null) {
group.remove(this);
group = null;
}
/* Aggressively null out all reference fields: see bug 4006245 */
target = null;
/* Speed the release of some of these resources */
threadLocals = null;
inheritableThreadLocals = null;
inheritedAccessControlContext = null;
blocker = null;
uncaughtExceptionHandler = null;
}
@Deprecated
public final void stop() {
// If the thread is already dead, return.
// A zero status value corresponds to "NEW".
if ((threadStatus != 0) && !isAlive()) {
return;
}
stop1(new ThreadDeath());
}
@Deprecated
public final synchronized void stop(Throwable obj) {
stop1(obj);
}
/**
* Common impl for stop() and stop(Throwable).
*/
private final synchronized void stop1(Throwable th) {
SecurityManager security = System.getSecurityManager();
if (security != null) {
checkAccess();
if ((this != Thread.currentThread())
|| (!(th instanceof ThreadDeath))) {
security
.checkPermission(SecurityConstants.STOP_THREAD_PERMISSION);
}
}
// A zero status value corresponds to "NEW"
if (threadStatus != 0) {
resume(); // Wake up thread if it was suspended; no-op otherwise
stop0(th);
} else {
// Must do the null arg check that the VM would do with stop0
if (th == null) {
throw new NullPointerException();
}
// Remember this stop attempt for if/when start is used
stopBeforeStart = true;
throwableFromStop = th;
}
}
/**
* Interrupts this thread.
*
* <p>
* Unless the current thread is interrupting itself, which is always
* permitted, the {@link #checkAccess() checkAccess} method of this thread
* is invoked, which may cause a {@link SecurityException} to be thrown.
*
* <p>
* If this thread is blocked in an invocation of the {@link Object#wait()
* wait()}, {@link Object#wait(long) wait(long)}, or
* {@link Object#wait(long, int) wait(long, int)} methods of the
* {@link Object} class, or of the {@link #join()}, {@link #join(long)},
* {@link #join(long, int)}, {@link #sleep(long)}, or
* {@link #sleep(long, int)}, methods of this class, then its interrupt
* status will be cleared and it will receive an
* {@link InterruptedException}.
*
* <p>
* If this thread is blocked in an I/O operation upon an
* {@link java.nio.channels.InterruptibleChannel </code>interruptible
* channel<code>} then the channel will be closed, the thread's interrupt
* status will be set, and the thread will receive a
* {@link java.nio.channels.ClosedByInterruptException}.
*
* <p> If this thread is blocked in a {@link java.nio.channels.Selector}
* then the thread's interrupt status will be set and it will return
* immediately from the selection operation, possibly with a non-zero value,
* just as if the selector's {@link java.nio.channels.Selector#wakeup
* wakeup} method were invoked.
*
* <p> If none of the previous conditions hold then this thread's interrupt
* status will be set.
* </p>
*
* <p>
* Interrupting a thread that is not alive need not have any effect.
*
* @throws SecurityException
* if the current thread cannot modify this thread
*
* @revised 6.0
* @spec JSR-51
*/
public void interrupt() {
if (this != Thread.currentThread())
checkAccess();
synchronized (blockerLock) {
Interruptible b = blocker;
if (b != null) {
interrupt0(); // Just to set the interrupt flag
b.interrupt();
return;
}
}
interrupt0();
}
/**
* Tests whether the current thread has been interrupted. The <i>interrupted
* status</i> of the thread is cleared by this method. In other words, if
* this method were to be called twice in succession, the second call would
* return false (unless the current thread were interrupted again, after the
* first call had cleared its interrupted status and before the second call
* had examined it).
*
* <p>
* A thread interruption ignored because a thread was not alive at the time
* of the interrupt will be reflected by this method returning false.
*
* @return <code>true</code> if the current thread has been interrupted;
* <code>false</code> otherwise.
* @see #isInterrupted()
* @revised 6.0
*/
public static boolean interrupted() {
return currentThread().isInterrupted(true);
}
/**
* Tests whether this thread has been interrupted. The <i>interrupted
* status</i> of the thread is unaffected by this method.
*
* <p>
* A thread interruption ignored because a thread was not alive at the time
* of the interrupt will be reflected by this method returning false.
*
* @return <code>true</code> if this thread has been interrupted;
* <code>false</code> otherwise.
* @see #interrupted()
* @revised 6.0
*/
public boolean isInterrupted() {
return isInterrupted(false);
}
/**
* Tests if some Thread has been interrupted. The interrupted state is reset
* or not based on the value of ClearInterrupted that is passed.
*/
private native boolean isInterrupted(boolean ClearInterrupted);
@Deprecated
public void destroy() {
throw new NoSuchMethodError();
}
/**
* Tests if this thread is alive. A thread is alive if it has been started
* and has not yet died.
*
* @return <code>true</code> if this thread is alive; <code>false</code>
* otherwise.
*/
public final native boolean isAlive();
@Deprecated
public final void suspend() {
checkAccess();
suspend0();
}
@Deprecated
public final void resume() {
checkAccess();
resume0();
}
/**
* Changes the priority of this thread.
* <p>
* First the <code>checkAccess</code> method of this thread is called with
* no arguments. This may result in throwing a
* <code>SecurityException</code>.
* <p>
* Otherwise, the priority of this thread is set to the smaller of the
* specified <code>newPriority</code> and the maximum permitted priority of
* the thread's thread group.
*
* @param newPriority
* priority to set this thread to
* @exception IllegalArgumentException
* If the priority is not in the range
* <code>MIN_PRIORITY</code> to <code>MAX_PRIORITY</code>.
* @exception SecurityException
* if the current thread cannot modify this thread.
* @see #getPriority
* @see #checkAccess()
* @see #getThreadGroup()
* @see #MAX_PRIORITY
* @see #MIN_PRIORITY
* @see ThreadGroup#getMaxPriority()
*/
public final void setPriority(int newPriority) {
ThreadGroup g;
checkAccess();
if (newPriority > MAX_PRIORITY || newPriority < MIN_PRIORITY) {
throw new IllegalArgumentException();
}
if ((g = getThreadGroup()) != null) {
if (newPriority > g.getMaxPriority()) {
newPriority = g.getMaxPriority();
}
setPriority0(priority = newPriority);
}
}
/**
* Returns this thread's priority.
*
* @return this thread's priority.
* @see #setPriority
*/
public final int getPriority() {
return priority;
}
/**
* Changes the name of this thread to be equal to the argument
* <code>name</code>.
* <p>
* First the <code>checkAccess</code> method of this thread is called with
* no arguments. This may result in throwing a
* <code>SecurityException</code>.
*
* @param name
* the new name for this thread.
* @exception SecurityException
* if the current thread cannot modify this thread.
* @see #getName
* @see #checkAccess()
*/
public final void setName(String name) {
checkAccess();
this.name = name.toCharArray();
}
/**
* Returns this thread's name.
*
* @return this thread's name.
* @see #setName(String)
*/
public final String getName() {
return String.valueOf(name);
}
/**
* Returns the thread group to which this thread belongs. This method
* returns null if this thread has died (been stopped).
*
* @return this thread's thread group.
*/
public final ThreadGroup getThreadGroup() {
return group;
}
/**
* Returns the number of active threads in the current thread's thread
* group.
*
* @return the number of active threads in the current thread's thread
* group.
*/
public static int activeCount() {
return currentThread().getThreadGroup().activeCount();
}
/**
* Copies into the specified array every active thread in the current
* thread's thread group and its subgroups. This method simply calls the
* <code>enumerate</code> method of the current thread's thread group with
* the array argument.
* <p>
* First, if there is a security manager, that <code>enumerate</code> method
* calls the security manager's <code>checkAccess</code> method with the
* thread group as its argument. This may result in throwing a
* <code>SecurityException</code>.
*
* @param tarray
* an array of Thread objects to copy to
* @return the number of threads put into the array
* @exception SecurityException
* if a security manager exists and its
* <code>checkAccess</code> method doesn't allow the
* operation.
* @see ThreadGroup#enumerate(Thread[])
* @see SecurityManager#checkAccess(ThreadGroup)
*/
public static int enumerate(Thread tarray[]) {
return currentThread().getThreadGroup().enumerate(tarray);
}
@Deprecated
public native int countStackFrames();
/**
* Waits at most <code>millis</code> milliseconds for this thread to die. A
* timeout of <code>0</code> means to wait forever.
*
* @param millis
* the time to wait in milliseconds.
* @exception InterruptedException
* if any thread has interrupted the current thread. The
* <i>interrupted status</i> of the current thread is cleared
* when this exception is thrown.
*/
public final synchronized void join(long millis)
throws InterruptedException {
long base = System.currentTimeMillis();
long now = 0;
if (millis < 0) {
throw new IllegalArgumentException("timeout value is negative");
}
if (millis == 0) {
while (isAlive()) {
wait(0);
}
} else {
while (isAlive()) {
long delay = millis - now;
if (delay <= 0) {
break;
}
wait(delay);
now = System.currentTimeMillis() - base;
}
}
}
/**
* Waits at most <code>millis</code> milliseconds plus <code>nanos</code>
* nanoseconds for this thread to die.
*
* @param millis
* the time to wait in milliseconds.
* @param nanos
* 0-999999 additional nanoseconds to wait.
* @exception IllegalArgumentException
* if the value of millis is negative the value of nanos is
* not in the range 0-999999.
* @exception InterruptedException
* if any thread has interrupted the current thread. The
* <i>interrupted status</i> of the current thread is cleared
* when this exception is thrown.
*/
public final synchronized void join(long millis, int nanos)
throws InterruptedException {
if (millis < 0) {
throw new IllegalArgumentException("timeout value is negative");
}
if (nanos < 0 || nanos > 999999) {
throw new IllegalArgumentException(
"nanosecond timeout value out of range");
}
if (nanos >= 500000 || (nanos != 0 && millis == 0)) {
millis++;
}
join(millis);
}
/**
* Waits for this thread to die.
*
* @exception InterruptedException
* if any thread has interrupted the current thread. The
* <i>interrupted status</i> of the current thread is cleared
* when this exception is thrown.
*/
public final void join() throws InterruptedException {
join(0);
}
/**
* Prints a stack trace of the current thread to the standard error stream.
* This method is used only for debugging.
*
* @see Throwable#printStackTrace()
*/
public static void dumpStack() {
new Exception("Stack trace").printStackTrace();
}
/**
* Marks this thread as either a daemon thread or a user thread. The Java
* Virtual Machine exits when the only threads running are all daemon
* threads.
* <p>
* This method must be called before the thread is started.
* <p>
* This method first calls the <code>checkAccess</code> method of this
* thread with no arguments. This may result in throwing a
* <code>SecurityException </code>(in the current thread).
*
* @param on
* if <code>true</code>, marks this thread as a daemon thread.
* @exception IllegalThreadStateException
* if this thread is active.
* @exception SecurityException
* if the current thread cannot modify this thread.
* @see #isDaemon()
* @see #checkAccess
*/
public final void setDaemon(boolean on) {
checkAccess();
if (isAlive()) {
throw new IllegalThreadStateException();
}
daemon = on;
}
/**
* Tests if this thread is a daemon thread.
*
* @return <code>true</code> if this thread is a daemon thread;
* <code>false</code> otherwise.
* @see #setDaemon(boolean)
*/
public final boolean isDaemon() {
return daemon;
}
/**
* Determines if the currently running thread has permission to modify this
* thread.
* <p>
* If there is a security manager, its <code>checkAccess</code> method is
* called with this thread as its argument. This may result in throwing a
* <code>SecurityException</code>.
*
* @exception SecurityException
* if the current thread is not allowed to access this
* thread.
* @see SecurityManager#checkAccess(Thread)
*/
public final void checkAccess() {
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkAccess(this);
}
}
public String toString() {
ThreadGroup group = getThreadGroup();
if (group != null) {
return "Thread[" + getName() + "," + getPriority() + ","
+ group.getName() + "]";
} else {
return "Thread[" + getName() + "," + getPriority() + "," + "" + "]";
}
}
/**
* Returns the context ClassLoader for this Thread. The context ClassLoader
* is provided by the creator of the thread for use by code running in this
* thread when loading classes and resources. If not set, the default is the
* ClassLoader context of the parent Thread. The context ClassLoader of the
* primordial thread is typically set to the class loader used to load the
* application.
*
* <p>
* First, if there is a security manager, and the caller's class loader is
* not null and the caller's class loader is not the same as or an ancestor
* of the context class loader for the thread whose context class loader is
* being requested, then the security manager's <code>checkPermission</code>
* method is called with a <code>RuntimePermission("getClassLoader")</code>
* permission to see if it's ok to get the context ClassLoader..
*
* @return the context ClassLoader for this Thread
*
* @throws SecurityException
* if a security manager exists and its
* <code>checkPermission</code> method doesn't allow getting the
* context ClassLoader.
* @see #setContextClassLoader
* @see SecurityManager#checkPermission
* @see RuntimePermission
*
* @since 1.2
*/
public ClassLoader getContextClassLoader() {
if (contextClassLoader == null)
return null;
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
ClassLoader ccl = ClassLoader.getCallerClassLoader();
if (ccl != null && ccl != contextClassLoader
&& !contextClassLoader.isAncestor(ccl)) {
sm
.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
}
}
return contextClassLoader;
}
public void setContextClassLoader(ClassLoader cl) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new RuntimePermission("setContextClassLoader"));
}
contextClassLoader = cl;
}
/**
* Returns <tt>true</tt> if and only if the current thread holds the monitor
* lock on the specified object.
*
* <p>
* This method is designed to allow a program to assert that the current
* thread already holds a specified lock:
*
* <pre>
* assert Thread.holdsLock(obj);
* </pre>
*
* @param obj
* the object on which to test lock ownership
* @throws NullPointerException
* if obj is <tt>null</tt>
* @return <tt>true</tt> if the current thread holds the monitor lock on the
* specified object.
* @since 1.4
*/
public static native boolean holdsLock(Object obj);
private static final StackTraceElement[] EMPTY_STACK_TRACE = new StackTraceElement[0];
public StackTraceElement[] getStackTrace() {
if (this != Thread.currentThread()) {
// check for getStackTrace permission
SecurityManager security = System.getSecurityManager();
if (security != null) {
security
.checkPermission(SecurityConstants.GET_STACK_TRACE_PERMISSION);
}
if (!isAlive()) {
return EMPTY_STACK_TRACE;
}
return dumpThreads(new Thread[] { this })[0];
} else {
// Don't need JVM help for current thread
return (new Exception()).getStackTrace();
}
}
public static Map<Thread, StackTraceElement[]> getAllStackTraces() {
// check for getStackTrace permission
SecurityManager security = System.getSecurityManager();
if (security != null) {
security
.checkPermission(SecurityConstants.GET_STACK_TRACE_PERMISSION);
security
.checkPermission(SecurityConstants.MODIFY_THREADGROUP_PERMISSION);
}
// Get a snapshot of the list of all threads
Thread[] threads = getThreads();
StackTraceElement[][] traces = dumpThreads(threads);
Map<Thread, StackTraceElement[]> m = new HashMap<Thread, StackTraceElement[]>(
threads.length);
for (int i = 0; i < threads.length; i++) {
if (threads[i].isAlive()) {
StackTraceElement[] stackTrace = traces[i];
if (stackTrace == null) {
stackTrace = EMPTY_STACK_TRACE;
}
m.put(threads[i], stackTrace);
}
}
return m;
}
private static final RuntimePermission SUBCLASS_IMPLEMENTATION_PERMISSION = new RuntimePermission(
"enableContextClassLoaderOverride");
/** cache of subclass security audit results */
private static final SoftCache subclassAudits = new SoftCache(10);
/**
* Verifies that this (possibly subclass) instance can be constructed
* without violating security constraints: the subclass must not override
* security-sensitive non-final methods, or else the
* "enableContextClassLoaderOverride" RuntimePermission is checked.
*/
private static boolean isCCLOverridden(Class cl) {
if (cl == Thread.class)
return false;
Boolean result = null;
synchronized (subclassAudits) {
result = (Boolean) subclassAudits.get(cl);
if (result == null) {
/*
* Note: only new Boolean instances (i.e., not Boolean.TRUE or
* Boolean.FALSE) must be used as cache values, otherwise cache
* entry will pin associated class.
*/
result = new Boolean(auditSubclass(cl));
subclassAudits.put(cl, result);
}
}
return result.booleanValue();
}
/**
* Performs reflective checks on given subclass to verify that it doesn't
* override security-sensitive non-final methods. Returns true if the
* subclass overrides any of the methods, false otherwise.
*/
private static boolean auditSubclass(final Class subcl) {
Boolean result = (Boolean) AccessController
.doPrivileged(new PrivilegedAction() {
public Object run() {
for (Class cl = subcl; cl != Thread.class; cl = cl
.getSuperclass()) {
try {
cl.getDeclaredMethod("getContextClassLoader",
new Class[0]);
return Boolean.TRUE;
} catch (NoSuchMethodException ex) {
}
try {
Class[] params = { ClassLoader.class };
cl.getDeclaredMethod("setContextClassLoader",
params);
return Boolean.TRUE;
} catch (NoSuchMethodException ex) {
}
}
return Boolean.FALSE;
}
});
return result.booleanValue();
}
private native static StackTraceElement[][] dumpThreads(Thread[] threads);
private native static Thread[] getThreads();
public long getId() {
return tid;
}
public enum State {
NEW, RUNNABLE, WAITING, TIMED_WAITING, TERMINATED;
}
public State getState() {
return sun.misc.VM.toThreadState(threadStatus);
}
// Added in JSR-166
/**
* Interface for handlers invoked when a <tt>Thread</tt> abruptly terminates
* due to an uncaught exception.
* <p>
* When a thread is about to terminate due to an uncaught exception the Java
* Virtual Machine will query the thread for its
* <tt>UncaughtExceptionHandler</tt> using
* {@link #getUncaughtExceptionHandler} and will invoke the handler's
* <tt>uncaughtException</tt> method, passing the thread and the exception
* as arguments. If a thread has not had its
* <tt>UncaughtExceptionHandler</tt> explicitly set, then its
* <tt>ThreadGroup</tt> object acts as its <tt>UncaughtExceptionHandler</tt>
* . If the <tt>ThreadGroup</tt> object has no special requirements for
* dealing with the exception, it can forward the invocation to the
* {@linkplain #getDefaultUncaughtExceptionHandler default uncaught
* exception handler}.
*
* @see #setDefaultUncaughtExceptionHandler
* @see #setUncaughtExceptionHandler
* @see ThreadGroup#uncaughtException
* @since 1.5
*/
public interface UncaughtExceptionHandler {
/**
* Method invoked when the given thread terminates due to the given
* uncaught exception.
* <p>
* Any exception thrown by this method will be ignored by the Java
* Virtual Machine.
*
* @param t
* the thread
* @param e
* the exception
*/
void uncaughtException(Thread t, Throwable e);
}
// null unless explicitly set
private volatile UncaughtExceptionHandler uncaughtExceptionHandler;
// null unless explicitly set
private static volatile UncaughtExceptionHandler defaultUncaughtExceptionHandler;
/**
* Set the default handler invoked when a thread abruptly terminates due to
* an uncaught exception, and no other handler has been defined for that
* thread.
*
* <p>
* Uncaught exception handling is controlled first by the thread, then by
* the thread's {@link ThreadGroup} object and finally by the default
* uncaught exception handler. If the thread does not have an explicit
* uncaught exception handler set, and the thread's thread group (including
* parent thread groups) does not specialize its <tt>uncaughtException</tt>
* method, then the default handler's <tt>uncaughtException</tt> method will
* be invoked.
* <p>
* By setting the default uncaught exception handler, an application can
* change the way in which uncaught exceptions are handled (such as logging
* to a specific device, or file) for those threads that would already
* accept whatever "default" behavior the system provided.
*
* <p>
* Note that the default uncaught exception handler should not usually defer
* to the thread's <tt>ThreadGroup</tt> object, as that could cause infinite
* recursion.
*
* @param eh
* the object to use as the default uncaught exception handler.
* If <tt>null</tt> then there is no default handler.
*
* @throws SecurityException
* if a security manager is present and it denies <tt>
* {@link RuntimePermission}
* ("setDefaultUncaughtExceptionHandler")</tt>
*
* @see #setUncaughtExceptionHandler
* @see #getUncaughtExceptionHandler
* @see ThreadGroup#uncaughtException
* @since 1.5
*/
public static void setDefaultUncaughtExceptionHandler(
UncaughtExceptionHandler eh) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new RuntimePermission(
"setDefaultUncaughtExceptionHandler"));
}
defaultUncaughtExceptionHandler = eh;
}
/**
* Returns the default handler invoked when a thread abruptly terminates due
* to an uncaught exception. If the returned value is <tt>null</tt>, there
* is no default.
*
* @since 1.5
* @see #setDefaultUncaughtExceptionHandler
*/
public static UncaughtExceptionHandler getDefaultUncaughtExceptionHandler() {
return defaultUncaughtExceptionHandler;
}
/**
* Returns the handler invoked when this thread abruptly terminates due to
* an uncaught exception. If this thread has not had an uncaught exception
* handler explicitly set then this thread's <tt>ThreadGroup</tt> object is
* returned, unless this thread has terminated, in which case <tt>null</tt>
* is returned.
*
* @since 1.5
*/
public UncaughtExceptionHandler getUncaughtExceptionHandler() {
return uncaughtExceptionHandler != null ? uncaughtExceptionHandler
: group;
}
/**
* Set the handler invoked when this thread abruptly terminates due to an
* uncaught exception.
* <p>
* A thread can take full control of how it responds to uncaught exceptions
* by having its uncaught exception handler explicitly set. If no such
* handler is set then the thread's <tt>ThreadGroup</tt> object acts as its
* handler.
*
* @param eh
* the object to use as this thread's uncaught exception handler.
* If <tt>null</tt> then this thread has no explicit handler.
* @throws SecurityException
* if the current thread is not allowed to modify this thread.
* @see #setDefaultUncaughtExceptionHandler
* @see ThreadGroup#uncaughtException
* @since 1.5
*/
public void setUncaughtExceptionHandler(UncaughtExceptionHandler eh) {
checkAccess();
uncaughtExceptionHandler = eh;
}
/**
* Dispatch an uncaught exception to the handler. This method is intended to
* be called only by the JVM.
*/
private void dispatchUncaughtException(Throwable e) {
getUncaughtExceptionHandler().uncaughtException(this, e);
}
/* Some private helper methods */
private native void setPriority0(int newPriority);
private native void stop0(Object o);
private native void suspend0();
private native void resume0();
private native void interrupt0();
}