new: UnsafeAdapter

assira.lambda/src/main/java/net/ranides/assira/reflection/UnsafeAdapter.java

@@ -0,0 +1,869 @@
+package net.ranides.assira.reflection;
+
+import java.lang.reflect.Field;
+
+public interface UnsafeAdapter {
+
+    static UnsafeAdapter getInstance() throws ReflectiveOperationException {
+        var theUnsafe = Class.forName("sun.misc.Unsafe").getDeclaredField("theUnsafe");
+        theUnsafe.setAccessible(true);
+        return AdapterFactory.getSystem().cast(IClass.typeinfo(UnsafeAdapter.class), theUnsafe.get(null));
+    }
+
+    /**
+     * Fetches a value from a given Java variable.
+     * More specifically, fetches a field or array element within the given
+     * object {@code o} at the given offset, or (if {@code o} is null)
+     * from the memory address whose numerical value is the given offset.
+     * <p>
+     * The results are undefined unless one of the following cases is true:
+     * <ul>
+     * <li>The offset was obtained from {@link #objectFieldOffset} on
+     * the {@link Field} of some Java field and the object
+     * referred to by {@code o} is of a class compatible with that
+     * field's class.
+     *
+     * <li>The offset and object reference {@code o} (either null or
+     * non-null) were both obtained via {@link #staticFieldOffset}
+     * and {@link #staticFieldBase} (respectively) from the
+     * reflective {@link Field} representation of some Java field.
+     *
+     * <li>The object referred to by {@code o} is an array, and the offset
+     * is an integer of the form {@code B+N*S}, where {@code N} is
+     * a valid index into the array, and {@code B} and {@code S} are
+     * the values obtained by {@link #arrayBaseOffset} and {@link
+     * #arrayIndexScale} (respectively) from the array's class.  The value
+     * referred to is the {@code N}<em>th</em> element of the array.
+     *
+     * </ul>
+     * <p>
+     * If one of the above cases is true, the call references a specific Java
+     * variable (field or array element).  However, the results are undefined
+     * if that variable is not in fact of the type returned by this method.
+     * <p>
+     * This method refers to a variable by means of two parameters, and so
+     * it provides (in effect) a <em>double-register</em> addressing mode
+     * for Java variables.  When the object reference is null, this method
+     * uses its offset as an absolute address.  This is similar in operation
+     * to methods such as {@link #getInt(long)}, which provide (in effect) a
+     * <em>single-register</em> addressing mode for non-Java variables.
+     * However, because Java variables may have a different layout in memory
+     * from non-Java variables, programmers should not assume that these
+     * two addressing modes are ever equivalent.  Also, programmers should
+     * remember that offsets from the double-register addressing mode cannot
+     * be portably confused with longs used in the single-register addressing
+     * mode.
+     *
+     * @param o      Java heap object in which the variable resides, if any, else
+     *               null
+     * @param offset indication of where the variable resides in a Java heap
+     *               object, if any, else a memory address locating the variable
+     *               statically
+     * @return the value fetched from the indicated Java variable
+     * @throws RuntimeException No defined exceptions are thrown, not even
+     *                          {@link NullPointerException}
+     */
+    int getInt(Object o, long offset);
+
+    /**
+     * Stores a value into a given Java variable.
+     * <p>
+     * The first two parameters are interpreted exactly as with
+     * {@link #getInt(Object, long)} to refer to a specific
+     * Java variable (field or array element).  The given value
+     * is stored into that variable.
+     * <p>
+     * The variable must be of the same type as the method
+     * parameter {@code x}.
+     *
+     * @param o      Java heap object in which the variable resides, if any, else
+     *               null
+     * @param offset indication of where the variable resides in a Java heap
+     *               object, if any, else a memory address locating the variable
+     *               statically
+     * @param x      the value to store into the indicated Java variable
+     * @throws RuntimeException No defined exceptions are thrown, not even
+     *                          {@link NullPointerException}
+     */
+    void putInt(Object o, long offset, int x);
+
+    /**
+     * Fetches a reference value from a given Java variable.
+     *
+     * @see #getInt(Object, long)
+     */
+    Object getObject(Object o, long offset);
+
+    /**
+     * Stores a reference value into a given Java variable.
+     * <p>
+     * Unless the reference {@code x} being stored is either null
+     * or matches the field type, the results are undefined.
+     * If the reference {@code o} is non-null, card marks or
+     * other store barriers for that object (if the VM requires them)
+     * are updated.
+     *
+     * @see #putInt(Object, long, int)
+     */
+    void putObject(Object o, long offset, Object x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    boolean getBoolean(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putBoolean(Object o, long offset, boolean x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    byte getByte(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putByte(Object o, long offset, byte x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    short getShort(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putShort(Object o, long offset, short x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    char getChar(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putChar(Object o, long offset, char x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    long getLong(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putLong(Object o, long offset, long x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    float getFloat(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putFloat(Object o, long offset, float x);
+
+    /**
+     * @see #getInt(Object, long)
+     */
+    double getDouble(Object o, long offset);
+
+    /**
+     * @see #putInt(Object, long, int)
+     */
+    void putDouble(Object o, long offset, double x);
+
+    /**
+     * Fetches a value from a given memory address.  If the address is zero, or
+     * does not point into a block obtained from {@link #allocateMemory}, the
+     * results are undefined.
+     *
+     * @see #allocateMemory
+     */
+    byte getByte(long address);
+
+    /**
+     * Stores a value into a given memory address.  If the address is zero, or
+     * does not point into a block obtained from {@link #allocateMemory}, the
+     * results are undefined.
+     *
+     * @see #getByte(long)
+     */
+    void putByte(long address, byte x);
+
+    /**
+     * @see #getByte(long)
+     */
+    short getShort(long address);
+
+    /**
+     * @see #putByte(long, byte)
+     */
+    void putShort(long address, short x);
+
+    /**
+     * @see #getByte(long)
+     */
+    char getChar(long address);
+
+    /**
+     * @see #putByte(long, byte)
+     */
+    void putChar(long address, char x);
+
+    /**
+     * @see #getByte(long)
+     */
+    int getInt(long address);
+
+    /**
+     * @see #putByte(long, byte)
+     */
+    void putInt(long address, int x);
+
+    /**
+     * @see #getByte(long)
+     */
+    long getLong(long address);
+
+    /**
+     * @see #putByte(long, byte)
+     */
+    void putLong(long address, long x);
+
+    /**
+     * @see #getByte(long)
+     */
+    float getFloat(long address);
+
+    /**
+     * @see #putByte(long, byte)
+     */
+    void putFloat(long address, float x);
+
+    /**
+     * @see #getByte(long)
+     */
+    double getDouble(long address);
+
+    /**
+     * @see #putByte(long, byte)
+     */
+    void putDouble(long address, double x);
+
+    /**
+     * Fetches a native pointer from a given memory address.  If the address is
+     * zero, or does not point into a block obtained from {@link
+     * #allocateMemory}, the results are undefined.
+     *
+     * <p>If the native pointer is less than 64 bits wide, it is extended as
+     * an unsigned number to a Java long.  The pointer may be indexed by any
+     * given byte offset, simply by adding that offset (as a simple integer) to
+     * the long representing the pointer.  The number of bytes actually read
+     * from the target address may be determined by consulting {@link
+     * #addressSize}.
+     *
+     * @see #allocateMemory
+     */
+    long getAddress(long address);
+
+    /**
+     * Stores a native pointer into a given memory address.  If the address is
+     * zero, or does not point into a block obtained from {@link
+     * #allocateMemory}, the results are undefined.
+     *
+     * <p>The number of bytes actually written at the target address may be
+     * determined by consulting {@link #addressSize}.
+     *
+     * @see #getAddress(long)
+     */
+    void putAddress(long address, long x);
+
+    /**
+     * Allocates a new block of native memory, of the given size in bytes.  The
+     * contents of the memory are uninitialized; they will generally be
+     * garbage.  The resulting native pointer will never be zero, and will be
+     * aligned for all value types.  Dispose of this memory by calling {@link
+     * #freeMemory}, or resize it with {@link #reallocateMemory}.
+     *
+     * <em>Note:</em> It is the resposibility of the caller to make
+     * sure arguments are checked before the methods are called. While
+     * some rudimentary checks are performed on the input, the checks
+     * are best effort and when performance is an overriding priority,
+     * as when methods of this class are optimized by the runtime
+     * compiler, some or all checks (if any) may be elided. Hence, the
+     * caller must not rely on the checks and corresponding
+     * exceptions!
+     *
+     * @throws RuntimeException if the size is negative or too large
+     *                          for the native size_t type
+     * @throws OutOfMemoryError if the allocation is refused by the system
+     * @see #getByte(long)
+     * @see #putByte(long, byte)
+     */
+    long allocateMemory(long bytes);
+
+    /**
+     * Resizes a new block of native memory, to the given size in bytes.  The
+     * contents of the new block past the size of the old block are
+     * uninitialized; they will generally be garbage.  The resulting native
+     * pointer will be zero if and only if the requested size is zero.  The
+     * resulting native pointer will be aligned for all value types.  Dispose
+     * of this memory by calling {@link #freeMemory}, or resize it with {@link
+     * #reallocateMemory}.  The address passed to this method may be null, in
+     * which case an allocation will be performed.
+     *
+     * <em>Note:</em> It is the resposibility of the caller to make
+     * sure arguments are checked before the methods are called. While
+     * some rudimentary checks are performed on the input, the checks
+     * are best effort and when performance is an overriding priority,
+     * as when methods of this class are optimized by the runtime
+     * compiler, some or all checks (if any) may be elided. Hence, the
+     * caller must not rely on the checks and corresponding
+     * exceptions!
+     *
+     * @throws RuntimeException if the size is negative or too large
+     *                          for the native size_t type
+     * @throws OutOfMemoryError if the allocation is refused by the system
+     * @see #allocateMemory
+     */
+    long reallocateMemory(long address, long bytes);
+
+    /**
+     * Sets all bytes in a given block of memory to a fixed value
+     * (usually zero).
+     *
+     * <p>This method determines a block's base address by means of two parameters,
+     * and so it provides (in effect) a <em>double-register</em> addressing mode,
+     * as discussed in {@link #getInt(Object, long)}.  When the object reference is null,
+     * the offset supplies an absolute base address.
+     *
+     * <p>The stores are in coherent (atomic) units of a size determined
+     * by the address and length parameters.  If the effective address and
+     * length are all even modulo 8, the stores take place in 'long' units.
+     * If the effective address and length are (resp.) even modulo 4 or 2,
+     * the stores take place in units of 'int' or 'short'.
+     *
+     * <em>Note:</em> It is the resposibility of the caller to make
+     * sure arguments are checked before the methods are called. While
+     * some rudimentary checks are performed on the input, the checks
+     * are best effort and when performance is an overriding priority,
+     * as when methods of this class are optimized by the runtime
+     * compiler, some or all checks (if any) may be elided. Hence, the
+     * caller must not rely on the checks and corresponding
+     * exceptions!
+     *
+     * @throws RuntimeException if any of the arguments is invalid
+     * @since 1.7
+     */
+    void setMemory(Object o, long offset, long bytes, byte value);
+
+    /**
+     * Sets all bytes in a given block of memory to a fixed value
+     * (usually zero).  This provides a <em>single-register</em> addressing mode,
+     * as discussed in {@link #getInt(Object, long)}.
+     *
+     * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
+     */
+    void setMemory(long address, long bytes, byte value);
+
+    /**
+     * Sets all bytes in a given block of memory to a copy of another
+     * block.
+     *
+     * <p>This method determines each block's base address by means of two parameters,
+     * and so it provides (in effect) a <em>double-register</em> addressing mode,
+     * as discussed in {@link #getInt(Object, long)}.  When the object reference is null,
+     * the offset supplies an absolute base address.
+     *
+     * <p>The transfers are in coherent (atomic) units of a size determined
+     * by the address and length parameters.  If the effective addresses and
+     * length are all even modulo 8, the transfer takes place in 'long' units.
+     * If the effective addresses and length are (resp.) even modulo 4 or 2,
+     * the transfer takes place in units of 'int' or 'short'.
+     *
+     * <em>Note:</em> It is the resposibility of the caller to make
+     * sure arguments are checked before the methods are called. While
+     * some rudimentary checks are performed on the input, the checks
+     * are best effort and when performance is an overriding priority,
+     * as when methods of this class are optimized by the runtime
+     * compiler, some or all checks (if any) may be elided. Hence, the
+     * caller must not rely on the checks and corresponding
+     * exceptions!
+     *
+     * @throws RuntimeException if any of the arguments is invalid
+     * @since 1.7
+     */
+    void copyMemory(Object srcBase, long srcOffset,
+                           Object destBase, long destOffset,
+                           long bytes);
+
+    /**
+     * Sets all bytes in a given block of memory to a copy of another
+     * block.  This provides a <em>single-register</em> addressing mode,
+     * as discussed in {@link #getInt(Object, long)}.
+     * <p>
+     * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
+     */
+    void copyMemory(long srcAddress, long destAddress, long bytes);
+
+    /**
+     * Disposes of a block of native memory, as obtained from {@link
+     * #allocateMemory} or {@link #reallocateMemory}.  The address passed to
+     * this method may be null, in which case no action is taken.
+     *
+     * <em>Note:</em> It is the resposibility of the caller to make
+     * sure arguments are checked before the methods are called. While
+     * some rudimentary checks are performed on the input, the checks
+     * are best effort and when performance is an overriding priority,
+     * as when methods of this class are optimized by the runtime
+     * compiler, some or all checks (if any) may be elided. Hence, the
+     * caller must not rely on the checks and corresponding
+     * exceptions!
+     *
+     * @throws RuntimeException if any of the arguments is invalid
+     * @see #allocateMemory
+     */
+    void freeMemory(long address);
+
+    /**
+     * Reports the location of a given field in the storage allocation of its
+     * class.  Do not expect to perform any sort of arithmetic on this offset;
+     * it is just a cookie which is passed to the unsafe heap memory accessors.
+     *
+     * <p>Any given field will always have the same offset and base, and no
+     * two distinct fields of the same class will ever have the same offset
+     * and base.
+     *
+     * <p>As of 1.4.1, offsets for fields are represented as long values,
+     * although the Sun JVM does not use the most significant 32 bits.
+     * However, JVM implementations which store static fields at absolute
+     * addresses can use long offsets and null base pointers to express
+     * the field locations in a form usable by {@link #getInt(Object, long)}.
+     * Therefore, code which will be ported to such JVMs on 64-bit platforms
+     * must preserve all bits of static field offsets.
+     *
+     * @see #getInt(Object, long)
+     */
+    long objectFieldOffset(Field f);
+
+    /**
+     * Reports the location of a given static field, in conjunction with {@link
+     * #staticFieldBase}.
+     * <p>Do not expect to perform any sort of arithmetic on this offset;
+     * it is just a cookie which is passed to the unsafe heap memory accessors.
+     *
+     * <p>Any given field will always have the same offset, and no two distinct
+     * fields of the same class will ever have the same offset.
+     *
+     * <p>As of 1.4.1, offsets for fields are represented as long values,
+     * although the Sun JVM does not use the most significant 32 bits.
+     * It is hard to imagine a JVM technology which needs more than
+     * a few bits to encode an offset within a non-array object,
+     * However, for consistency with other methods in this class,
+     * this method reports its result as a long value.
+     *
+     * @see #getInt(Object, long)
+     */
+    long staticFieldOffset(Field f);
+
+    /**
+     * Reports the location of a given static field, in conjunction with {@link
+     * #staticFieldOffset}.
+     * <p>Fetch the base "Object", if any, with which static fields of the
+     * given class can be accessed via methods like {@link #getInt(Object,
+     * long)}.  This value may be null.  This value may refer to an object
+     * which is a "cookie", not guaranteed to be a real Object, and it should
+     * not be used in any way except as argument to the get and put routines in
+     * this class.
+     */
+    Object staticFieldBase(Field f);
+
+    /**
+     * Detects if the given class may need to be initialized. This is often
+     * needed in conjunction with obtaining the static field base of a
+     * class.
+     *
+     * @return false only if a call to {@code ensureClassInitialized} would have no effect
+     */
+    boolean shouldBeInitialized(Class<?> c);
+
+    /**
+     * Ensures the given class has been initialized. This is often
+     * needed in conjunction with obtaining the static field base of a
+     * class.
+     */
+    void ensureClassInitialized(Class<?> c);
+
+    /**
+     * Reports the offset of the first element in the storage allocation of a
+     * given array class.  If {@link #arrayIndexScale} returns a non-zero value
+     * for the same class, you may use that scale factor, together with this
+     * base offset, to form new offsets to access elements of arrays of the
+     * given class.
+     *
+     * @see #getInt(Object, long)
+     * @see #putInt(Object, long, int)
+     */
+    int arrayBaseOffset(Class<?> arrayClass);
+
+    /**
+     * Reports the scale factor for addressing elements in the storage
+     * allocation of a given array class.  However, arrays of "narrow" types
+     * will generally not work properly with accessors like {@link
+     * #getByte(Object, long)}, so the scale factor for such classes is reported
+     * as zero.
+     *
+     * @see #arrayBaseOffset
+     * @see #getInt(Object, long)
+     * @see #putInt(Object, long, int)
+     */
+    int arrayIndexScale(Class<?> arrayClass);
+
+    /**
+     * Reports the size in bytes of a native pointer, as stored via {@link
+     * #putAddress}.  This value will be either 4 or 8.  Note that the sizes of
+     * other primitive types (as stored in native memory blocks) is determined
+     * fully by their information content.
+     */
+    int addressSize();
+
+    /**
+     * Reports the size in bytes of a native memory page (whatever that is).
+     * This value will always be a power of two.
+     */
+    int pageSize();
+
+    /**
+     * Defines a class but does not make it known to the class loader or system dictionary.
+     * <p>
+     * For each CP entry, the corresponding CP patch must either be null or have
+     * the a format that matches its tag:
+     * <ul>
+     * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
+     * <li>Utf8: a string (must have suitable syntax if used as signature or name)
+     * <li>Class: any java.lang.Class object
+     * <li>String: any object (not just a java.lang.String)
+     * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
+     * </ul>
+     *
+     * @param hostClass context for linkage, access control, protection domain, and class loader
+     * @param data      bytes of a class file
+     * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
+     */
+    Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches);
+
+    /**
+     * Allocates an instance but does not run any constructor.
+     * Initializes the class if it has not yet been.
+     */
+    Object allocateInstance(Class<?> cls);
+
+    /**
+     * Throws the exception without telling the verifier.
+     */
+    void throwException(Throwable ee);
+
+    /**
+     * Atomically updates Java variable to {@code x} if it is currently
+     * holding {@code expected}.
+     *
+     * <p>This operation has memory semantics of a {@code volatile} read
+     * and write.  Corresponds to C11 atomic_compare_exchange_strong.
+     *
+     * @return {@code true} if successful
+     */
+    boolean compareAndSwapObject(Object o, long offset,
+                                        Object expected,
+                                        Object x);
+
+    /**
+     * Atomically updates Java variable to {@code x} if it is currently
+     * holding {@code expected}.
+     *
+     * <p>This operation has memory semantics of a {@code volatile} read
+     * and write.  Corresponds to C11 atomic_compare_exchange_strong.
+     *
+     * @return {@code true} if successful
+     */
+    boolean compareAndSwapInt(Object o, long offset, int expected, int x);
+
+    /**
+     * Atomically updates Java variable to {@code x} if it is currently
+     * holding {@code expected}.
+     *
+     * <p>This operation has memory semantics of a {@code volatile} read
+     * and write.  Corresponds to C11 atomic_compare_exchange_strong.
+     *
+     * @return {@code true} if successful
+     */
+    boolean compareAndSwapLong(Object o, long offset, long expected, long x);
+
+    /**
+     * Fetches a reference value from a given Java variable, with volatile
+     * load semantics. Otherwise identical to {@link #getObject(Object, long)}
+     */
+    Object getObjectVolatile(Object o, long offset);
+
+    /**
+     * Stores a reference value into a given Java variable, with
+     * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
+     */
+    void putObjectVolatile(Object o, long offset, Object x);
+
+    /**
+     * Volatile version of {@link #getInt(Object, long)}
+     */
+    int getIntVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putInt(Object, long, int)}
+     */
+    void putIntVolatile(Object o, long offset, int x);
+
+    /**
+     * Volatile version of {@link #getBoolean(Object, long)}
+     */
+    boolean getBooleanVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putBoolean(Object, long, boolean)}
+     */
+    void putBooleanVolatile(Object o, long offset, boolean x);
+
+    /**
+     * Volatile version of {@link #getByte(Object, long)}
+     */
+    byte getByteVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putByte(Object, long, byte)}
+     */
+    void putByteVolatile(Object o, long offset, byte x);
+
+    /**
+     * Volatile version of {@link #getShort(Object, long)}
+     */
+    short getShortVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putShort(Object, long, short)}
+     */
+    void putShortVolatile(Object o, long offset, short x);
+
+    /**
+     * Volatile version of {@link #getChar(Object, long)}
+     */
+    char getCharVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putChar(Object, long, char)}
+     */
+    void putCharVolatile(Object o, long offset, char x);
+
+    /**
+     * Volatile version of {@link #getLong(Object, long)}
+     */
+    long getLongVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putLong(Object, long, long)}
+     */
+    void putLongVolatile(Object o, long offset, long x);
+
+    /**
+     * Volatile version of {@link #getFloat(Object, long)}
+     */
+    float getFloatVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putFloat(Object, long, float)}
+     */
+    void putFloatVolatile(Object o, long offset, float x);
+
+    /**
+     * Volatile version of {@link #getDouble(Object, long)}
+     */
+    double getDoubleVolatile(Object o, long offset);
+
+    /**
+     * Volatile version of {@link #putDouble(Object, long, double)}
+     */
+    void putDoubleVolatile(Object o, long offset, double x);
+
+    /**
+     * Version of {@link #putObjectVolatile(Object, long, Object)}
+     * that does not guarantee immediate visibility of the store to
+     * other threads. This method is generally only useful if the
+     * underlying field is a Java volatile (or if an array cell, one
+     * that is otherwise only accessed using volatile accesses).
+     * <p>
+     * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
+     */
+    void putOrderedObject(Object o, long offset, Object x);
+
+    /**
+     * Ordered/Lazy version of {@link #putIntVolatile(Object, long, int)}
+     */
+    void putOrderedInt(Object o, long offset, int x);
+
+    /**
+     * Ordered/Lazy version of {@link #putLongVolatile(Object, long, long)}
+     */
+    void putOrderedLong(Object o, long offset, long x);
+
+    /**
+     * Unblocks the given thread blocked on {@code park}, or, if it is
+     * not blocked, causes the subsequent call to {@code park} not to
+     * block.  Note: this operation is "unsafe" solely because the
+     * caller must somehow ensure that the thread has not been
+     * destroyed. Nothing special is usually required to ensure this
+     * when called from Java (in which there will ordinarily be a live
+     * reference to the thread) but this is not nearly-automatically
+     * so when calling from native code.
+     *
+     * @param thread the thread to unpark.
+     */
+    void unpark(Object thread);
+
+    /**
+     * Blocks current thread, returning when a balancing
+     * {@code unpark} occurs, or a balancing {@code unpark} has
+     * already occurred, or the thread is interrupted, or, if not
+     * absolute and time is not zero, the given time nanoseconds have
+     * elapsed, or if absolute, the given deadline in milliseconds
+     * since Epoch has passed, or spuriously (i.e., returning for no
+     * "reason"). Note: This operation is in the Unsafe class only
+     * because {@code unpark} is, so it would be strange to place it
+     * elsewhere.
+     */
+    void park(boolean isAbsolute, long time);
+
+    /**
+     * Gets the load average in the system run queue assigned
+     * to the available processors averaged over various periods of time.
+     * This method retrieves the given {@code nelem} samples and
+     * assigns to the elements of the given {@code loadavg} array.
+     * The system imposes a maximum of 3 samples, representing
+     * averages over the last 1,  5,  and  15 minutes, respectively.
+     *
+     * @param loadavg an array of double of size nelems
+     * @param nelems  the number of samples to be retrieved and
+     *                must be 1 to 3.
+     * @return the number of samples actually retrieved; or -1
+     * if the load average is unobtainable.
+     */
+    int getLoadAverage(double[] loadavg, int nelems);
+
+    /**
+     * Atomically adds the given value to the current value of a field
+     * or array element within the given object {@code o}
+     * at the given {@code offset}.
+     *
+     * @param o      object/array to update the field/element in
+     * @param offset field/element offset
+     * @param delta  the value to add
+     * @return the previous value
+     * @since 1.8
+     */
+    int getAndAddInt(Object o, long offset, int delta);
+
+    /**
+     * Atomically adds the given value to the current value of a field
+     * or array element within the given object {@code o}
+     * at the given {@code offset}.
+     *
+     * @param o      object/array to update the field/element in
+     * @param offset field/element offset
+     * @param delta  the value to add
+     * @return the previous value
+     * @since 1.8
+     */
+    long getAndAddLong(Object o, long offset, long delta);
+
+    /**
+     * Atomically exchanges the given value with the current value of
+     * a field or array element within the given object {@code o}
+     * at the given {@code offset}.
+     *
+     * @param o        object/array to update the field/element in
+     * @param offset   field/element offset
+     * @param newValue new value
+     * @return the previous value
+     * @since 1.8
+     */
+    int getAndSetInt(Object o, long offset, int newValue);
+
+    /**
+     * Atomically exchanges the given value with the current value of
+     * a field or array element within the given object {@code o}
+     * at the given {@code offset}.
+     *
+     * @param o        object/array to update the field/element in
+     * @param offset   field/element offset
+     * @param newValue new value
+     * @return the previous value
+     * @since 1.8
+     */
+    long getAndSetLong(Object o, long offset, long newValue);
+
+    /**
+     * Atomically exchanges the given reference value with the current
+     * reference value of a field or array element within the given
+     * object {@code o} at the given {@code offset}.
+     *
+     * @param o        object/array to update the field/element in
+     * @param offset   field/element offset
+     * @param newValue new value
+     * @return the previous value
+     * @since 1.8
+     */
+    Object getAndSetObject(Object o, long offset, Object newValue);
+
+    /**
+     * Ensures that loads before the fence will not be reordered with loads and
+     * stores after the fence; a "LoadLoad plus LoadStore barrier".
+     * <p>
+     * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
+     * (an "acquire fence").
+     * <p>
+     * A pure LoadLoad fence is not provided, since the addition of LoadStore
+     * is almost always desired, and most current hardware instructions that
+     * provide a LoadLoad barrier also provide a LoadStore barrier for free.
+     *
+     * @since 1.8
+     */
+    void loadFence();
+
+    /**
+     * Ensures that loads and stores before the fence will not be reordered with
+     * stores after the fence; a "StoreStore plus LoadStore barrier".
+     * <p>
+     * Corresponds to C11 atomic_thread_fence(memory_order_release)
+     * (a "release fence").
+     * <p>
+     * A pure StoreStore fence is not provided, since the addition of LoadStore
+     * is almost always desired, and most current hardware instructions that
+     * provide a StoreStore barrier also provide a LoadStore barrier for free.
+     *
+     * @since 1.8
+     */
+    void storeFence();
+
+    /**
+     * Ensures that loads and stores before the fence will not be reordered
+     * with loads and stores after the fence.  Implies the effects of both
+     * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
+     * barrier.
+     * <p>
+     * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
+     *
+     * @since 1.8
+     */
+    void fullFence();
+
+}